Time Alignment Timer Information

ABSTRACT

A base station distributed unit may transmit a timing advance command for a timing advance group to a wireless device. The base station distributed unit may start a time alignment timer for the timing advance group of the wireless device in response to the transmission of the timing advance command. The base station distributed unit may determine expiration of the time alignment timer. The base station distributed unit may transmit a first message to a base station central unit. The first message may indicate the expiration of the time alignment timer for the timing advance group of the wireless device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 62/543,836, filed Aug. 10, 2017, U.S. Provisional PatentApplication No. 62/543,839, filed Aug. 10, 2017, U.S. Provisional PatentApplication No. 62/543,841, filed Aug. 10, 2017, and U.S. ProvisionalPatent Application No. 62/543,847, filed Aug. 10, 2017, which are herebyincorporated by reference in their entirety.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Examples of several of the various embodiments of the present inventionare described herein with reference to the drawings.

FIG. 1 is a diagram depicting example sets of OFDM subcarriers as per anaspect of an embodiment of the present invention.

FIG. 2 is a diagram depicting an example transmission time and receptiontime for two carriers in a carrier group as per an aspect of anembodiment of the present invention.

FIG. 3 is a diagram depicting OFDM radio resources as per an aspect ofan embodiment of the present invention.

FIG. 4 is a block diagram of a base station and a wireless device as peran aspect of an embodiment of the present invention.

FIG. 5A, FIG. 5B, FIG. 5C and FIG. 5D are example diagrams for uplinkand downlink signal transmission as per an aspect of an embodiment ofthe present invention.

FIG. 6 is an example diagram for a protocol structure withmulti-connectivity as per an aspect of an embodiment of the presentinvention.

FIG. 7 is an example diagram for a protocol structure with CA and DC asper an aspect of an embodiment of the present invention.

FIG. 8 shows example TAG configurations as per an aspect of anembodiment of the present invention.

FIG. 9 is an example message flow in a random access process in asecondary TAG as per an aspect of an embodiment of the presentinvention.

FIG. 10A and FIG. 10B are example diagrams for interfaces between a 5Gcore network (e.g. NGC) and base stations (e.g. gNB and eLTE eNB) as peran aspect of an embodiment of the present invention.

FIG. 11A, FIG. 11B, FIG. 11C, FIG. 11D, FIG. 11E, and FIG. 11F areexample diagrams for architectures of tight interworking between 5G RAN(e.g. gNB) and LTE RAN (e.g. (e)LTE eNB) as per an aspect of anembodiment of the present invention.

FIG. 12A, FIG. 12B, and FIG. 12C are example diagrams for radio protocolstructures of tight interworking bearers as per an aspect of anembodiment of the present invention.

FIG. 13A and FIG. 13B are example diagrams for gNB deployment scenariosas per an aspect of an embodiment of the present invention.

FIG. 14 is an example diagram for functional split option examples ofthe centralized gNB deployment scenario as per an aspect of anembodiment of the present invention.

FIG. 15 is an example diagram of an aspect of an embodiment of thepresent disclosure.

FIG. 16 is an example diagram of an aspect of an embodiment of thepresent disclosure.

FIG. 17 is an example diagram of an aspect of an embodiment of thepresent disclosure.

FIG. 18 is an example diagram of an aspect of an embodiment of thepresent disclosure.

FIG. 19 is an example diagram of an aspect of an embodiment of thepresent disclosure.

FIG. 20 is an example diagram of an aspect of an embodiment of thepresent disclosure.

FIG. 21 is an example diagram of an aspect of an embodiment of thepresent disclosure.

FIG. 22 is an example diagram of an aspect of an embodiment of thepresent disclosure.

FIG. 23 is an example diagram of an aspect of an embodiment of thepresent disclosure.

FIG. 24 is an example diagram of an aspect of an embodiment of thepresent disclosure.

FIG. 25 is an example diagram of an aspect of an embodiment of thepresent disclosure.

FIG. 26 is an example diagram of an aspect of an embodiment of thepresent disclosure.

FIG. 27 is an example diagram of an aspect of an embodiment of thepresent disclosure.

FIG. 28 is an example diagram of an aspect of an embodiment of thepresent disclosure.

FIG. 29 is an example diagram of an aspect of an embodiment of thepresent disclosure.

FIG. 30 is an example diagram of an aspect of an embodiment of thepresent disclosure.

FIG. 31 is an example diagram of an aspect of an embodiment of thepresent disclosure.

FIG. 32 is an example diagram of an aspect of an embodiment of thepresent disclosure.

FIG. 33 is an example diagram of an aspect of an embodiment of thepresent disclosure.

FIG. 34 is an example diagram of an aspect of an embodiment of thepresent disclosure.

FIG. 35 is an example diagram of an aspect of an embodiment of thepresent disclosure.

FIG. 36 is an example diagram of an aspect of an embodiment of thepresent disclosure.

FIG. 37 is an example diagram of an aspect of an embodiment of thepresent disclosure.

FIG. 38 is a flow diagram of an aspect of an embodiment of the presentdisclosure.

FIG. 39 is a flow diagram of an aspect of an embodiment of the presentdisclosure.

FIG. 40 is a flow diagram of an aspect of an embodiment of the presentdisclosure.

FIG. 41 is a flow diagram of an aspect of an embodiment of the presentdisclosure.

FIG. 42 is a flow diagram of an aspect of an embodiment of the presentdisclosure.

FIG. 43 is a flow diagram of an aspect of an embodiment of the presentdisclosure.

FIG. 44 is a flow diagram of an aspect of an embodiment of the presentdisclosure.

FIG. 45 is a flow diagram of an aspect of an embodiment of the presentdisclosure.

FIG. 46 is a flow diagram of an aspect of an embodiment of the presentdisclosure.

FIG. 47 is a flow diagram of an aspect of an embodiment of the presentdisclosure.

FIG. 48 is a flow diagram of an aspect of an embodiment of the presentdisclosure.

FIG. 49 is a flow diagram of an aspect of an embodiment of the presentdisclosure.

FIG. 50 is a flow diagram of an aspect of an embodiment of the presentdisclosure.

FIG. 51 is a flow diagram of an aspect of an embodiment of the presentdisclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Example embodiments of the present invention enable operation ofwireless communication systems. Embodiments of the technology disclosedherein may be employed in the technical field of multicarriercommunication systems. More particularly, the embodiments of thetechnology disclosed herein may relate to cellular wireless systems in amulticarrier communication systems.

The following Acronyms are used throughout the present disclosure:

ASIC application-specific integrated circuit

BPSK binary phase shift keying

CA carrier aggregation

CSI channel state information

CDMA code division multiple access

CSS common search space

CPLD complex programmable logic devices

CC component carrier

CP cyclic prefix

DL downlink

DCI downlink control information

DC dual connectivity

eMBB enhanced mobile broadband

EPC evolved packet core

E-UTRAN evolved-universal terrestrial radio access network

FPGA field programmable gate arrays

FDD frequency division multiplexing

HDL hardware description languages

HARQ hybrid automatic repeat request

IE information element

LTE long term evolution

MCG master cell group

MeNB master evolved node B

MIB master information block

MAC media access control

MAC media access control

MME mobility management entity

mMTC massive machine type communications

NAS non-access stratum

NR new radio

OFDM orthogonal frequency division multiplexing

PDCP packet data convergence protocol

PDU packet data unit

PHY physical

PDCCH physical downlink control channel

PHICH physical HARQ indicator channel

PUCCH physical uplink control channel

PUSCH physical uplink shared channel

PCell primary cell

PCell primary cell

PCC primary component carrier

PSCell primary secondary cell

pTAG primary timing advance group

QAM quadrature amplitude modulation

QPSK quadrature phase shift keying

RBG resource block groups

RLC radio link control

RRC radio resource control

RA random access

RB resource blocks

SCC secondary component carrier

SCell secondary cell

Scell secondary cells

SCG secondary cell group

SeNB secondary evolved node B

sTAGs secondary timing advance group

SDU service data unit

S-GW serving gateway

SRB signaling radio bearer

SC-OFDM single carrier-OFDM

SFN system frame number

SIB system information block

TAI tracking area identifier

TAT time alignment timer

TDD time division duplexing

TDMA time division multiple access

TA timing advance

TAG timing advance group

TTI transmission time intervalTB transport block

UL uplink

UE user equipment

URLLC ultra-reliable low-latency communications

VHDL VHSIC hardware description language

CU central unit

DU distributed unit

Fs-C Fs-control plane

Fs-U Fs-user plane

gNB next generation node B

NGC next generation core

NG CP next generation control plane core

NG-C NG-control plane

NG-U NG-user plane

NR new radio

NR MAC new radio MAC

NR PHY new radio physical

NR PDCP new radio PDCP

NR RLC new radio RLC

NR RRC new radio RRC

NSSAI network slice selection assistance information

PLMN public land mobile network

UPGW user plane gateway

Xn-C Xn-control plane

Xn-U Xn-user plane

Xx-C Xx-control plane

Xx-U Xx-user plane

Example embodiments of the invention may be implemented using variousphysical layer modulation and transmission mechanisms. Exampletransmission mechanisms may include, but are not limited to: CDMA, OFDM,TDMA, Wavelet technologies, and/or the like. Hybrid transmissionmechanisms such as TDMA/CDMA, and OFDM/CDMA may also be employed.Various modulation schemes may be applied for signal transmission in thephysical layer. Examples of modulation schemes include, but are notlimited to: phase, amplitude, code, a combination of these, and/or thelike. An example radio transmission method may implement QAM using BPSK,QPSK, 16-QAM, 64-QAM, 256-QAM, and/or the like. Physical radiotransmission may be enhanced by dynamically or semi-dynamically changingthe modulation and coding scheme depending on transmission requirementsand radio conditions.

FIG. 1 is a diagram depicting example sets of OFDM subcarriers as per anaspect of an embodiment of the present invention. As illustrated in thisexample, arrow(s) in the diagram may depict a subcarrier in amulticarrier OFDM system. The OFDM system may use technology such asOFDM technology, DFTS-OFDM, SC-OFDM technology, or the like. Forexample, arrow 101 shows a subcarrier transmitting information symbols.FIG. 1 is for illustration purposes, and a typical multicarrier OFDMsystem may include more subcarriers in a carrier. For example, thenumber of subcarriers in a carrier may be in the range of 10 to 10,000subcarriers. FIG. 1 shows two guard bands 106 and 107 in a transmissionband. As illustrated in FIG. 1, guard band 106 is between subcarriers103 and subcarriers 104. The example set of subcarriers A 102 includessubcarriers 103 and subcarriers 104. FIG. 1 also illustrates an exampleset of subcarriers B 105. As illustrated, there is no guard band betweenany two subcarriers in the example set of subcarriers B 105. Carriers ina multicarrier OFDM communication system may be contiguous carriers,non-contiguous carriers, or a combination of both contiguous andnon-contiguous carriers.

FIG. 2 is a diagram depicting an example transmission time and receptiontime for two carriers as per an aspect of an embodiment of the presentinvention. A multicarrier OFDM communication system may include one ormore carriers, for example, ranging from 1 to 10 carriers. Carrier A 204and carrier B 205 may have the same or different timing structures.Although FIG. 2 shows two synchronized carriers, carrier A 204 andcarrier B 205 may or may not be synchronized with each other. Differentradio frame structures may be supported for FDD and TDD duplexmechanisms. FIG. 2 shows an example FDD frame timing. Downlink anduplink transmissions may be organized into radio frames 201. In thisexample, radio frame duration is 10 msec. Other frame durations, forexample, in the range of 1 to 100 msec may also be supported. In thisexample, each 10 ms radio frame 201 may be divided into ten equallysized subframes 202. Other subframe durations such as including 0.5msec, 1 msec, 2 msec, and 5 msec may also be supported. Subframe(s) mayconsist of two or more slots (e.g. slots 206 and 207). For the exampleof FDD, 10 subframes may be available for downlink transmission and 10subframes may be available for uplink transmissions in each 10 msinterval. Uplink and downlink transmissions may be separated in thefrequency domain. A slot may be 7 or 14 OFDM symbols for the samesubcarrier spacing of up to 60 kHz with normal CP. A slot may be 14 OFDMsymbols for the same subcarrier spacing higher than 60 kHz with normalCP. A slot may contain all downlink, all uplink, or a downlink part andan uplink part and/or alike. Slot aggregation may be supported, e.g.,data transmission may be scheduled to span one or multiple slots. In anexample, a mini-slot may start at an OFDM symbol in a subframe. Amini-slot may have a duration of one or more OFDM symbols. Slot(s) mayinclude a plurality of OFDM symbols 203. The number of OFDM symbols 203in a slot 206 may depend on the cyclic prefix length and subcarrierspacing.

FIG. 3 is a diagram depicting OFDM radio resources as per an aspect ofan embodiment of the present invention. The resource grid structure intime 304 and frequency 305 is illustrated in FIG. 3. The quantity ofdownlink subcarriers or RBs may depend, at least in part, on thedownlink transmission bandwidth 306 configured in the cell. The smallestradio resource unit may be called a resource element (e.g. 301).Resource elements may be grouped into resource blocks (e.g. 302).Resource blocks may be grouped into larger radio resources calledResource Block Groups (RBG) (e.g. 303). The transmitted signal in slot206 may be described by one or several resource grids of a plurality ofsubcarriers and a plurality of OFDM symbols. Resource blocks may be usedto describe the mapping of certain physical channels to resourceelements. Other pre-defined groupings of physical resource elements maybe implemented in the system depending on the radio technology. Forexample, 24 subcarriers may be grouped as a radio block for a durationof 5 msec. In an illustrative example, a resource block may correspondto one slot in the time domain and 180 kHz in the frequency domain (for15 KHz subcarrier bandwidth and 12 subcarriers).

In an example embodiment, multiple numerologies may be supported. In anexample, a numerology may be derived by scaling a basic subcarrierspacing by an integer N. In an example, scalable numerology may allow atleast from 15 kHz to 480 kHz subcarrier spacing. The numerology with 15kHz and scaled numerology with different subcarrier spacing with thesame CP overhead may align at a symbol boundary every 1 ms in a NRcarrier.

FIG. 5A, FIG. 5B, FIG. 5C and FIG. 5D are example diagrams for uplinkand downlink signal transmission as per an aspect of an embodiment ofthe present invention. FIG. 5A shows an example uplink physical channel.The baseband signal representing the physical uplink shared channel mayperform the following processes. These functions are illustrated asexamples and it is anticipated that other mechanisms may be implementedin various embodiments. The functions may comprise scrambling,modulation of scrambled bits to generate complex-valued symbols, mappingof the complex-valued modulation symbols onto one or severaltransmission layers, transform precoding to generate complex-valuedsymbols, precoding of the complex-valued symbols, mapping of precodedcomplex-valued symbols to resource elements, generation ofcomplex-valued time-domain DFTS-OFDM/SC-FDMA signal for each antennaport, and/or the like.

Example modulation and up-conversion to the carrier frequency of thecomplex-valued DFTS-OFDM/SC-FDMA baseband signal for each antenna portand/or the complex-valued PRACH baseband signal is shown in FIG. 5B.Filtering may be employed prior to transmission.

An example structure for Downlink Transmissions is shown in FIG. 5C. Thebaseband signal representing a downlink physical channel may perform thefollowing processes. These functions are illustrated as examples and itis anticipated that other mechanisms may be implemented in variousembodiments. The functions include scrambling of coded bits in each ofthe codewords to be transmitted on a physical channel; modulation ofscrambled bits to generate complex-valued modulation symbols; mapping ofthe complex-valued modulation symbols onto one or several transmissionlayers; precoding of the complex-valued modulation symbols on each layerfor transmission on the antenna ports; mapping of complex-valuedmodulation symbols for each antenna port to resource elements;generation of complex-valued time-domain OFDM signal for each antennaport, and/or the like.

Example modulation and up-conversion to the carrier frequency of thecomplex-valued OFDM baseband signal for each antenna port is shown inFIG. 5D. Filtering may be employed prior to transmission.

FIG. 4 is an example block diagram of a base station 401 and a wirelessdevice 406, as per an aspect of an embodiment of the present invention.A communication network 400 may include at least one base station 401and at least one wireless device 406. The base station 401 may includeat least one communication interface 402, at least one processor 403,and at least one set of program code instructions 405 stored innon-transitory memory 404 and executable by the at least one processor403. The wireless device 406 may include at least one communicationinterface 407, at least one processor 408, and at least one set ofprogram code instructions 410 stored in non-transitory memory 409 andexecutable by the at least one processor 408. Communication interface402 in base station 401 may be configured to engage in communicationwith communication interface 407 in wireless device 406 via acommunication path that includes at least one wireless link 411.Wireless link 411 may be a bi-directional link. Communication interface407 in wireless device 406 may also be configured to engage in acommunication with communication interface 402 in base station 401. Basestation 401 and wireless device 406 may be configured to send andreceive data over wireless link 411 using multiple frequency carriers.According to some of the various aspects of embodiments, transceiver(s)may be employed. A transceiver is a device that includes both atransmitter and receiver. Transceivers may be employed in devices suchas wireless devices, base stations, relay nodes, and/or the like.Example embodiments for radio technology implemented in communicationinterface 402, 407 and wireless link 411 are illustrated are FIG. 1,FIG. 2, FIG. 3, FIG. 5, and associated text.

An interface may be a hardware interface, a firmware interface, asoftware interface, and/or a combination thereof. The hardware interfacemay include connectors, wires, electronic devices such as drivers,amplifiers, and/or the like. A software interface may include codestored in a memory device to implement protocol(s), protocol layers,communication drivers, device drivers, combinations thereof, and/or thelike. A firmware interface may include a combination of embeddedhardware and code stored in and/or in communication with a memory deviceto implement connections, electronic device operations, protocol(s),protocol layers, communication drivers, device drivers, hardwareoperations, combinations thereof, and/or the like.

The term configured may relate to the capacity of a device whether thedevice is in an operational or non-operational state. Configured mayalso refer to specific settings in a device that effect the operationalcharacteristics of the device whether the device is in an operational ornon-operational state. In other words, the hardware, software, firmware,registers, memory values, and/or the like may be “configured” within adevice, whether the device is in an operational or nonoperational state,to provide the device with specific characteristics. Terms such as “acontrol message to cause in a device” may mean that a control messagehas parameters that may be used to configure specific characteristics inthe device, whether the device is in an operational or non-operationalstate.

According to some of the various aspects of embodiments, a 5G networkmay include a multitude of base stations, providing a user plane NRPDCP/NR RLC/NR MAC/NR PHY and control plane (NR RRC) protocolterminations towards the wireless device. The base station(s) may beinterconnected with other base station(s) (e.g. employing an Xninterface). The base stations may also be connected employing, forexample, an NG interface to an NGC. FIG. 10A and FIG. 10B are examplediagrams for interfaces between a 5G core network (e.g. NGC) and basestations (e.g. gNB and eLTE eNB) as per an aspect of an embodiment ofthe present invention. For example, the base stations may beinterconnected to the NGC control plane (e.g. NG CP) employing the NG-Cinterface and to the NGC user plane (e.g. UPGW) employing the NG-Uinterface. The NG interface may support a many-to-many relation between5G core networks and base stations.

A base station may include many sectors for example: 1, 2, 3, 4, or 6sectors. A base station may include many cells, for example, rangingfrom 1 to 50 cells or more. A cell may be categorized, for example, as aprimary cell or secondary cell. At RRC connectionestablishment/re-establishment/handover, one serving cell may providethe NAS (non-access stratum) mobility information (e.g. TAI), and at RRCconnection re-establishment/handover, one serving cell may provide thesecurity input. This cell may be referred to as the Primary Cell(PCell). In the downlink, the carrier corresponding to the PCell may bethe Downlink Primary Component Carrier (DL PCC), while in the uplink, itmay be the Uplink Primary Component Carrier (UL PCC). Depending onwireless device capabilities, Secondary Cells (SCells) may be configuredto form together with the PCell a set of serving cells. In the downlink,the carrier corresponding to an SCell may be a Downlink SecondaryComponent Carrier (DL SCC), while in the uplink, it may be an UplinkSecondary Component Carrier (UL SCC). An SCell may or may not have anuplink carrier.

A cell, comprising a downlink carrier and optionally an uplink carrier,may be assigned a physical cell ID and a cell index. A carrier (downlinkor uplink) may belong to only one cell. The cell ID or Cell index mayalso identify the downlink carrier or uplink carrier of the cell(depending on the context it is used). In the specification, cell ID maybe equally referred to a carrier ID, and cell index may be referred tocarrier index. In implementation, the physical cell ID or cell index maybe assigned to a cell. A cell ID may be determined using asynchronization signal transmitted on a downlink carrier. A cell indexmay be determined using RRC messages. For example, when thespecification refers to a first physical cell ID for a first downlinkcarrier, the specification may mean the first physical cell ID is for acell comprising the first downlink carrier. The same concept may applyto, for example, carrier activation. When the specification indicatesthat a first carrier is activated, the specification may equally meanthat the cell comprising the first carrier is activated.

Embodiments may be configured to operate as needed. The disclosedmechanism may be performed when certain criteria are met, for example,in a wireless device, a base station, a radio environment, a network, acombination of the above, and/or the like. Example criteria may bebased, at least in part, on for example, traffic load, initial systemset up, packet sizes, traffic characteristics, a combination of theabove, and/or the like. When the one or more criteria are met, variousexample embodiments may be applied. Therefore, it may be possible toimplement example embodiments that selectively implement disclosedprotocols.

A base station may communicate with a mix of wireless devices. Wirelessdevices may support multiple technologies, and/or multiple releases ofthe same technology. Wireless devices may have some specificcapability(ies) depending on its wireless device category and/orcapability(ies). A base station may comprise multiple sectors. When thisdisclosure refers to a base station communicating with a plurality ofwireless devices, this disclosure may refer to a subset of the totalwireless devices in a coverage area. This disclosure may refer to, forexample, a plurality of wireless devices of a given LTE or 5G releasewith a given capability and in a given sector of the base station. Theplurality of wireless devices in this disclosure may refer to a selectedplurality of wireless devices, and/or a subset of total wireless devicesin a coverage area which perform according to disclosed methods, and/orthe like. There may be a plurality of wireless devices in a coveragearea that may not comply with the disclosed methods, for example,because those wireless devices perform based on older releases of LTE or5G technology.

FIG. 6 and FIG. 7 are example diagrams for protocol structure with CAand multi-connectivity as per an aspect of an embodiment of the presentinvention. NR may support multi-connectivity operation whereby amultiple RX/TX UE in RRC_CONNECTED may be configured to utilize radioresources provided by multiple schedulers located in multiple gNBsconnected via a non-ideal or ideal backhaul over the Xn interface. gNBsinvolved in multi-connectivity for a certain UE may assume two differentroles: a gNB may either act as a master gNB or as a secondary gNB. Inmulti-connectivity, a UE may be connected to one master gNB and one ormore secondary gNBs. FIG. 7 illustrates one example structure for the UEside MAC entities when a Master Cell Group (MCG) and a Secondary CellGroup (SCG) are configured, and it may not restrict implementation.Media Broadcast Multicast Service (MBMS) reception is not shown in thisfigure for simplicity.

In multi-connectivity, the radio protocol architecture that a particularbearer uses may depend on how the bearer is setup. Three alternativesmay exist, an MCG bearer, an SCG bearer and a split bearer as shown inFIG. 6. NR RRC may be located in master gNB and SRBs may be configuredas a MCG bearer type and may use the radio resources of the master gNB.Multi-connectivity may also be described as having at least one bearerconfigured to use radio resources provided by the secondary gNB.Multi-connectivity may or may not be configured/implemented in exampleembodiments of the invention.

In the case of multi-connectivity, the UE may be configured withmultiple NR MAC entities: one NR MAC entity for master gNB, and other NRMAC entities for secondary gNBs. In multi-connectivity, the configuredset of serving cells for a UE may comprise of two subsets: the MasterCell Group (MCG) containing the serving cells of the master gNB, and theSecondary Cell Groups (SCGs) containing the serving cells of thesecondary gNBs. For a SCG, one or more of the following may be applied:at least one cell in the SCG has a configured UL CC and one of them,named PSCell (or PCell of SCG, or sometimes called PCell), is configuredwith PUCCH resources; when the SCG is configured, there may be at leastone SCG bearer or one Split bearer; upon detection of a physical layerproblem or a random access problem on a PSCell, or the maximum number ofNR RLC retransmissions has been reached associated with the SCG, or upondetection of an access problem on a PSCell during a SCG addition or aSCG change: a RRC connection re-establishment procedure may not betriggered, UL transmissions towards cells of the SCG are stopped, amaster gNB may be informed by the UE of a SCG failure type, for splitbearer, the DL data transfer over the master gNB is maintained; the NRRLC AM bearer may be configured for the split bearer; like PCell, PSCellmay not be de-activated; PSCell may be changed with a SCG change (e.g.with security key change and a RACH procedure); and/or a direct bearertype change between a Split bearer and a SCG bearer or simultaneousconfiguration of a SCG and a Split bearer may or may not supported.

With respect to the interaction between a master gNB and secondary gNBsfor multi-connectivity, one or more of the following principles may beapplied: the master gNB may maintain the RRM measurement configurationof the UE and may, (e.g, based on received measurement reports ortraffic conditions or bearer types), decide to ask a secondary gNB toprovide additional resources (serving cells) for a UE; upon receiving arequest from the master gNB, a secondary gNB may create a container thatmay result in the configuration of additional serving cells for the UE(or decide that it has no resource available to do so); for UEcapability coordination, the master gNB may provide (part of) the ASconfiguration and the UE capabilities to the secondary gNB; the mastergNB and the secondary gNB may exchange information about a UEconfiguration by employing of NR RRC containers (inter-node messages)carried in Xn messages; the secondary gNB may initiate a reconfigurationof its existing serving cells (e.g., PUCCH towards the secondary gNB);the secondary gNB may decide which cell is the PSCell within the SCG;the master gNB may or may not change the content of the NR RRCconfiguration provided by the secondary gNB; in the case of a SCGaddition and a SCG SCell addition, the master gNB may provide the latestmeasurement results for the SCG cell(s); both a master gNB and secondarygNBs may know the SFN and subframe offset of each other by OAM, (e.g.,for the purpose of DRX alignment and identification of a measurementgap). In an example, when adding a new SCG SCell, dedicated NR RRCsignaling may be used for sending required system information of thecell as for CA, except for the SFN acquired from a MIB of the PSCell ofa SCG.

In an example, serving cells may be grouped in a TA group (TAG). Servingcells in one TAG may use the same timing reference. For a given TAG,user equipment (UE) may use at least one downlink carrier as a timingreference. For a given TAG, a UE may synchronize uplink subframe andframe transmission timing of uplink carriers belonging to the same TAG.In an example, serving cells having an uplink to which the same TAapplies may correspond to serving cells hosted by the same receiver. AUE supporting multiple TAs may support two or more TA groups. One TAgroup may contain the PCell and may be called a primary TAG (pTAG). In amultiple TAG configuration, at least one TA group may not contain thePCell and may be called a secondary TAG (sTAG). In an example, carrierswithin the same TA group may use the same TA value and/or the sametiming reference. When DC is configured, cells belonging to a cell group(MCG or SCG) may be grouped into multiple TAGs including a pTAG and oneor more sTAGs.

FIG. 8 shows example TAG configurations as per an aspect of anembodiment of the present invention. In Example 1, pTAG comprises PCell,and an sTAG comprises SCell1. In Example 2, a pTAG comprises a PCell andSCell1, and an sTAG comprises SCell2 and SCell3. In Example 3, pTAGcomprises PCell and SCell1, and an sTAG1 includes SCell2 and SCell3, andsTAG2 comprises SCell4. Up to four TAGs may be supported in a cell group(MCG or SCG) and other example TAG configurations may also be provided.In various examples in this disclosure, example mechanisms are describedfor a pTAG and an sTAG. Some of the example mechanisms may be applied toconfigurations with multiple sTAGs.

In an example, an eNB may initiate an RA procedure via a PDCCH order foran activated SCell. This PDCCH order may be sent on a scheduling cell ofthis SCell. When cross carrier scheduling is configured for a cell, thescheduling cell may be different than the cell that is employed forpreamble transmission, and the PDCCH order may include an SCell index.At least a non-contention based RA procedure may be supported forSCell(s) assigned to sTAG(s).

FIG. 9 is an example message flow in a random access process in asecondary TAG as per an aspect of an embodiment of the presentinvention. An eNB transmits an activation command 600 to activate anSCell. A preamble 602 (Msg1) may be sent by a UE in response to a PDCCHorder 601 on an SCell belonging to an sTAG. In an example embodiment,preamble transmission for SCells may be controlled by the network usingPDCCH format 1A. Msg2 message 603 (RAR: random access response) inresponse to the preamble transmission on the SCell may be addressed toRA-RNTI in a PCell common search space (CSS). Uplink packets 604 may betransmitted on the SCell in which the preamble was transmitted.

According to some of the various aspects of embodiments, initial timingalignment may be achieved through a random access procedure. This mayinvolve a UE transmitting a random access preamble and an eNB respondingwith an initial TA command NTA (amount of timing advance) within arandom access response window. The start of the random access preamblemay be aligned with the start of a corresponding uplink subframe at theUE assuming NTA=0. The eNB may estimate the uplink timing from therandom access preamble transmitted by the UE. The TA command may bederived by the eNB based on the estimation of the difference between thedesired UL timing and the actual UL timing. The UE may determine theinitial uplink transmission timing relative to the correspondingdownlink of the sTAG on which the preamble is transmitted.

The mapping of a serving cell to a TAG may be configured by a servingeNB with RRC signaling. The mechanism for TAG configuration andreconfiguration may be based on RRC signaling. According to some of thevarious aspects of embodiments, when an eNB performs an SCell additionconfiguration, the related TAG configuration may be configured for theSCell. In an example embodiment, an eNB may modify the TAG configurationof an SCell by removing (releasing) the SCell and adding(configuring) anew SCell (with the same physical cell ID and frequency) with an updatedTAG ID. The new SCell with the updated TAG ID may initially be inactivesubsequent to being assigned the updated TAG ID. The eNB may activatethe updated new SCell and start scheduling packets on the activatedSCell. In an example implementation, it may not be possible to changethe TAG associated with an SCell, but rather, the SCell may need to beremoved and a new SCell may need to be added with another TAG. Forexample, if there is a need to move an SCell from an sTAG to a pTAG, atleast one RRC message, for example, at least one RRC reconfigurationmessage, may be send to the UE to reconfigure TAG configurations byreleasing the SCell and then configuring the SCell as a part of the pTAG(when an SCell is added/configured without a TAG index, the SCell may beexplicitly assigned to the pTAG). The PCell may not change its TA groupand may be a member of the pTAG.

The purpose of an RRC connection reconfiguration procedure may be tomodify an RRC connection, (e.g. to establish, modify and/or release RBs,to perform handover, to setup, modify, and/or release measurements, toadd, modify, and/or release SCells). If the received RRC ConnectionReconfiguration message includes the sCellToReleaseList, the UE mayperform an SCell release. If the received RRC Connection Reconfigurationmessage includes the sCellToAddModList, the UE may perform SCelladditions or modification.

In LTE Release-10 and Release-11 CA, a PUCCH is only transmitted on thePCell (PSCell) to an eNB. In LTE-Release 12 and earlier, a UE maytransmit PUCCH information on one cell (PCell or PSCell) to a given eNB.

As the number of CA capable UEs and also the number of aggregatedcarriers increase, the number of PUCCHs and also the PUCCH payload sizemay increase. Accommodating the PUCCH transmissions on the PCell maylead to a high PUCCH load on the PCell. A PUCCH on an SCell may beintroduced to offload the PUCCH resource from the PCell. More than onePUCCH may be configured for example, a PUCCH on a PCell and anotherPUCCH on an SCell. In the example embodiments, one, two or more cellsmay be configured with PUCCH resources for transmitting CSI/ACK/NACK toa base station. Cells may be grouped into multiple PUCCH groups, and oneor more cell within a group may be configured with a PUCCH. In anexample configuration, one SCell may belong to one PUCCH group. SCellswith a configured PUCCH transmitted to a base station may be called aPUCCH SCell, and a cell group with a common PUCCH resource transmittedto the same base station may be called a PUCCH group.

In an example embodiment, a MAC entity may have a configurable timertimeAlignmentTimer per TAG. The timeAlignmentTimer may be used tocontrol how long the MAC entity considers the Serving Cells belonging tothe associated TAG to be uplink time aligned. The MAC entity may, when aTiming Advance Command MAC control element is received, apply the TimingAdvance Command for the indicated TAG; start or restart thetimeAlignmentTimer associated with the indicated TAG. The MAC entitymay, when a Timing Advance Command is received in a Random AccessResponse message for a serving cell belonging to a TAG and/or if theRandom Access Preamble was not selected by the MAC entity, apply theTiming Advance Command for this TAG and start or restart thetimeAlignmentTimer associated with this TAG. Otherwise, if thetimeAlignmentTimer associated with this TAG is not running, the TimingAdvance Command for this TAG may be applied and the timeAlignmentTimerassociated with this TAG started. When the contention resolution isconsidered not successful, a timeAlignmentTimer associated with this TAGmay be stopped. Otherwise, the MAC entity may ignore the received TimingAdvance Command.

In example embodiments, a timer is running once it is started, until itis stopped or until it expires; otherwise it may not be running. A timercan be started if it is not running or restarted if it is running. Forexample, a timer may be started or restarted from its initial value.

Example embodiments of the invention may enable operation ofmulti-carrier communications. Other example embodiments may comprise anon-transitory tangible computer readable media comprising instructionsexecutable by one or more processors to cause operation of multi-carriercommunications. Yet other example embodiments may comprise an article ofmanufacture that comprises a non-transitory tangible computer readablemachine-accessible medium having instructions encoded thereon forenabling programmable hardware to cause a device (e.g. wirelesscommunicator, UE, base station, etc.) to enable operation ofmulti-carrier communications. The device may include processors, memory,interfaces, and/or the like. Other example embodiments may comprisecommunication networks comprising devices such as base stations,wireless devices (or user equipment: UE), servers, switches, antennas,and/or the like.

FIG. 11A, FIG. 11B, FIG. 11C, FIG. 11D, FIG. 11E, and FIG. 11F areexample diagrams for architectures of tight interworking between 5G RANand LTE RAN as per an aspect of an embodiment of the present invention.The tight interworking may enable a multiple RX/TX UE in RRC_CONNECTEDto be configured to utilize radio resources provided by two schedulerslocated in two base stations (e.g. (e)LTE eNB and gNB) connected via anon-ideal or ideal backhaul over the Xx interface between LTE eNB andgNB or the Xn interface between eLTE eNB and gNB. Base stations involvedin tight interworking for a certain UE may assume two different roles: abase station may either act as a master base station or as a secondarybase station. In tight interworking, a UE may be connected to one masterbase station and one secondary base station. Mechanisms implemented intight interworking may be extended to cover more than two base stations.

In FIG. 11A and FIG. 11B, a master base station may be an LTE eNB, whichmay be connected to EPC nodes (e.g. to an MME via the S1-C interface andto an S-GW via the S1-U interface), and a secondary base station may bea gNB, which may be a non-standalone node having a control planeconnection via an Xx-C interface to an LTE eNB. In the tightinterworking architecture of FIG. 11A, a user plane for a gNB may beconnected to an S-GW through an LTE eNB via an Xx-U interface betweenLTE eNB and gNB and an S1-U interface between LTE eNB and S-GW. In thearchitecture of FIG. 11B, a user plane for a gNB may be connecteddirectly to an S-GW via an S1-U interface between gNB and S-GW.

In FIG. 11C and FIG. 11D, a master base station may be a gNB, which maybe connected to NGC nodes (e.g. to a control plane core node via theNG-C interface and to a user plane core node via the NG-U interface),and a secondary base station may be an eLTE eNB, which may be anon-standalone node having a control plane connection via an Xn-Cinterface to a gNB. In the tight interworking architecture of FIG. 11C,a user plane for an eLTE eNB may be connected to a user plane core nodethrough a gNB via an Xn-U interface between eLTE eNB and gNB and an NG-Uinterface between gNB and user plane core node. In the architecture ofFIG. 11D, a user plane for an eLTE eNB may be connected directly to auser plane core node via an NG-U interface between eLTE eNB and userplane core node.

In FIG. 11E and FIG. 11F, a master base station may be an eLTE eNB,which may be connected to NGC nodes (e.g. to a control plane core nodevia the NG-C interface and to a user plane core node via the NG-Uinterface), and a secondary base station may be a gNB, which may be anon-standalone node having a control plane connection via an Xn-Cinterface to an eLTE eNB. In the tight interworking architecture of FIG.11E, a user plane for a gNB may be connected to a user plane core nodethrough an eLTE eNB via an Xn-U interface between eLTE eNB and gNB andan NG-U interface between eLTE eNB and user plane core node. In thearchitecture of FIG. 11F, a user plane for a gNB may be connecteddirectly to a user plane core node via an NG-U interface between gNB anduser plane core node.

FIG. 12A, FIG. 12B, and FIG. 12C are example diagrams for radio protocolstructures of tight interworking bearers as per an aspect of anembodiment of the present invention. In FIG. 12A, an LTE eNB may be amaster base station, and a gNB may be a secondary base station. In FIG.12B, a gNB may be a master base station, and an eLTE eNB may be asecondary base station. In FIG. 12C, an eLTE eNB may be a master basestation, and a gNB may be a secondary base station. In 5G network, theradio protocol architecture that a particular bearer uses may depend onhow the bearer is setup. Three alternatives may exist, an MCG bearer, anSCG bearer, and a split bearer as shown in FIG. 12A, FIG. 12B, and FIG.12C. NR RRC may be located in master base station, and SRBs may beconfigured as an MCG bearer type and may use the radio resources of themaster base station. Tight interworking may also be described as havingat least one bearer configured to use radio resources provided by thesecondary base station. Tight interworking may or may not beconfigured/implemented in example embodiments of the invention.

In the case of tight interworking, the UE may be configured with two MACentities: one MAC entity for master base station, and one MAC entity forsecondary base station. In tight interworking, the configured set ofserving cells for a UE may comprise of two subsets: the Master CellGroup (MCG) containing the serving cells of the master base station, andthe Secondary Cell Group (SCG) containing the serving cells of thesecondary base station. For a SCG, one or more of the following may beapplied: at least one cell in the SCG has a configured UL CC and one ofthem, named PSCell (or PCell of SCG, or sometimes called PCell), isconfigured with PUCCH resources; when the SCG is configured, there maybe at least one SCG bearer or one split bearer; upon detection of aphysical layer problem or a random access problem on a PSCell, or themaximum number of (NR) RLC retransmissions has been reached associatedwith the SCG, or upon detection of an access problem on a PSCell duringa SCG addition or a SCG change: a RRC connection re-establishmentprocedure may not be triggered, UL transmissions towards cells of theSCG are stopped, a master base station may be informed by the UE of aSCG failure type, for split bearer, the DL data transfer over the masterbase station is maintained; the RLC AM bearer may be configured for thesplit bearer; like PCell, PSCell may not be de-activated; PSCell may bechanged with a SCG change (e.g. with security key change and a RACHprocedure); and/or neither a direct bearer type change between a Splitbearer and a SCG bearer nor simultaneous configuration of a SCG and aSplit bearer are supported.

With respect to the interaction between a master base station and asecondary base station, one or more of the following principles may beapplied: the master base station may maintain the RRM measurementconfiguration of the UE and may, (e.g, based on received measurementreports, traffic conditions, or bearer types), decide to ask a secondarybase station to provide additional resources (serving cells) for a UE;upon receiving a request from the master base station, a secondary basestation may create a container that may result in the configuration ofadditional serving cells for the UE (or decide that it has no resourceavailable to do so); for UE capability coordination, the master basestation may provide (part of) the AS configuration and the UEcapabilities to the secondary base station; the master base station andthe secondary base station may exchange information about a UEconfiguration by employing of RRC containers (inter-node messages)carried in Xn or Xx messages; the secondary base station may initiate areconfiguration of its existing serving cells (e.g., PUCCH towards thesecondary base station); the secondary base station may decide whichcell is the PSCell within the SCG; the master base station may notchange the content of the RRC configuration provided by the secondarybase station; in the case of a SCG addition and a SCG SCell addition,the master base station may provide the latest measurement results forthe SCG cell(s); both a master base station and a secondary base stationmay know the SFN and subframe offset of each other by OAM, (e.g., forthe purpose of DRX alignment and identification of a measurement gap).In an example, when adding a new SCG SCell, dedicated RRC signaling maybe used for sending required system information of the cell as for CA,except for the SFN acquired from a MIB of the PSCell of a SCG.

FIG. 13A and FIG. 13B are example diagrams for gNB deployment scenariosas per an aspect of an embodiment of the present invention. In thenon-centralized deployment scenario in FIG. 13A, the full protocol stack(e.g. NR RRC, NR PDCP, NR RLC, NR MAC, and NR PHY) may be supported atone node. In the centralized deployment scenario in FIG. 13B, upperlayers of gNB may be located in a Central Unit (CU), and lower layers ofgNB may be located in Distributed Units (DU). The CU-DU interface (e.g.Fs interface) connecting CU and DU may be ideal or non-ideal. Fs-C mayprovide a control plane connection over Fs interface, and Fs-U mayprovide a user plane connection over Fs interface. In the centralizeddeployment, different functional split options between CU and DUs may bepossible by locating different protocol layers (RAN functions) in CU andDU. The functional split may support flexibility to move RAN functionsbetween CU and DU depending on service requirements and/or networkenvironments. The functional split option may change during operationafter Fs interface setup procedure, or may change only in Fs setupprocedure (i.e. static during operation after Fs setup procedure).

FIG. 14 is an example diagram for different functional split optionexamples of the centralized gNB deployment scenario as per an aspect ofan embodiment of the present invention. In the split option example 1,an NR RRC may be in CU, and NR PDCP, NR RLC, NR MAC, NR PHY, and RF maybe in DU. In the split option example 2, an NR RRC and NR PDCP may be inCU, and NR RLC, NR MAC, NR PHY, and RF may be in DU. In the split optionexample 3, an NR RRC, NR PDCP, and partial function of NR RLC may be inCU, and the other partial function of NR RLC, NR MAC, NR PHY, and RF maybe in DU. In the split option example 4, an NR RRC, NR PDCP, and NR RLCmay be in CU, and NR MAC, NR PHY, and RF may be in DU. In the splitoption example 5, an NR RRC, NR PDCP, NR RLC, and partial function of NRMAC may be in CU, and the other partial function of NR MAC, NR PHY, andRF may be in DU. In the split option example 6, an NR RRC, NR PDCP, NRRLC, and NR MAC may be in CU, and NR PHY and RF may be in DU. In thesplit option example 7, an NR RRC, NR PDCP, NR RLC, NR MAC, and partialfunction of NR PHY may be in CU, and the other partial function of NRPHY and RF may be in DU. In the split option example 8, an NR RRC, NRPDCP, NR RLC, NR MAC, and NR PHY may be in CU, and RF may be in DU.

The functional split may be configured per CU, per DU, per UE, perbearer, per slice, or with other granularities. In per CU split, a CUmay have a fixed split, and DUs may be configured to match the splitoption of CU. In per DU split, each DU may be configured with adifferent split, and a CU may provide different split options fordifferent DUs. In per UE split, a gNB (CU and DU) may provide differentsplit options for different UEs. In per bearer split, different splitoptions may be utilized for different bearer types. In per slice splice,different split options may be applied for different slices.

In an example embodiment, the new radio access network (new RAN) maysupport different network slices, which may allow differentiatedtreatment customized to support different service requirements with endto end scope. The new RAN may provide a differentiated handling oftraffic for different network slices that may be pre-configured, and mayallow a single RAN node to support multiple slices. The new RAN maysupport selection of a RAN part for a given network slice, by one ormore slice ID(s) or NSSAI(s) provided by a UE or a NGC (e.g. NG CP). Theslice ID(s) or NSSAI(s) may identify one or more of pre-configurednetwork slices in a PLMN. For initial attach, a UE may provide a sliceID and/or an NSSAI, and a RAN node (e.g. gNB) may use the slice ID orthe NSSAI for routing an initial NAS signaling to an NGC control planefunction (e.g. NG CP). If a UE does not provide any slice ID or NSSAI, aRAN node may send a NAS signaling to a default NGC control planefunction. For subsequent accesses, the UE may provide a temporary ID fora slice identification, which may be assigned by the NGC control planefunction, to enable a RAN node to route the NAS message to a relevantNGC control plane function. The new RAN may support resource isolationbetween slices. The RAN resource isolation may be achieved by avoidingthat shortage of shared resources in one slice breaks a service levelagreement for another slice.

The amount of data traffic carried over cellular networks is expected toincrease for many years to come. The number of users/devices isincreasing and each user/device accesses an increasing number andvariety of services, e.g. video delivery, large files, images. Thisrequires not only high capacity in the network, but also provisioningvery high data rates to meet customers' expectations on interactivityand responsiveness. More spectrum is therefore needed for cellularoperators to meet the increasing demand. Considering user expectationsof high data rates along with seamless mobility, it is beneficial thatmore spectrum be made available for deploying macro cells as well assmall cells for cellular systems.

Striving to meet the market demands, there has been increasing interestfrom operators in deploying some complementary access utilizingunlicensed spectrum to meet the traffic growth. This is exemplified bythe large number of operator-deployed Wi-Fi networks and the 3GPPstandardization of LTE/WLAN interworking solutions. This interestindicates that unlicensed spectrum, when present, can be an effectivecomplement to licensed spectrum for cellular operators to helpaddressing the traffic explosion in some scenarios, such as hotspotareas. LAA offers an alternative for operators to make use of unlicensedspectrum while managing one radio network, thus offering newpossibilities for optimizing the network's efficiency.

In an example embodiment, Listen-before-talk (clear channel assessment)may be implemented for transmission in an LAA cell. In alisten-before-talk (LBT) procedure, equipment may apply a clear channelassessment (CCA) check before using the channel. For example, the CCAutilizes at least energy detection to determine the presence or absenceof other signals on a channel in order to determine if a channel isoccupied or clear, respectively. For example, European and Japaneseregulations mandate the usage of LBT in the unlicensed bands. Apart fromregulatory requirements, carrier sensing via LBT may be one way for fairsharing of the unlicensed spectrum.

In an example embodiment, discontinuous transmission on an unlicensedcarrier with limited maximum transmission duration may be enabled. Someof these functions may be supported by one or more signals to betransmitted from the beginning of a discontinuous LAA downlinktransmission. Channel reservation may be enabled by the transmission ofsignals, by an LAA node, after gaining channel access via a successfulLBT operation, so that other nodes that receive the transmitted signalwith energy above a certain threshold sense the channel to be occupied.Functions that may need to be supported by one or more signals for LAAoperation with discontinuous downlink transmission may include one ormore of the following: detection of the LAA downlink transmission(including cell identification) by UEs; time & frequency synchronizationof UEs.

In an example embodiment, DL LAA design may employ subframe boundaryalignment according to LTE-A carrier aggregation timing relationshipsacross serving cells aggregated by CA. This may not imply that the eNBtransmissions can start only at the subframe boundary. LAA may supporttransmitting PDSCH when not all OFDM symbols are available fortransmission in a subframe according to LBT. Delivery of necessarycontrol information for the PDSCH may also be supported.

LBT procedure may be employed for fair and friendly coexistence of LAAwith other operators and technologies operating in unlicensed spectrum.LBT procedures on a node attempting to transmit on a carrier inunlicensed spectrum require the node to perform a clear channelassessment to determine if the channel is free for use. An LBT proceduremay involve at least energy detection to determine if the channel isbeing used. For example, regulatory requirements in some regions, e.g.,in Europe, specify an energy detection threshold such that if a nodereceives energy greater than this threshold, the node assumes that thechannel is not free. While nodes may follow such regulatoryrequirements, a node may optionally use a lower threshold for energydetection than that specified by regulatory requirements. In an example,LAA may employ a mechanism to adaptively change the energy detectionthreshold, e.g., LAA may employ a mechanism to adaptively lower theenergy detection threshold from an upper bound. Adaptation mechanism maynot preclude static or semi-static setting of the threshold. In anexample Category 4 LBT mechanism or other type of LBT mechanisms may beimplemented.

Various example LBT mechanisms may be implemented. In an example, forsome signals, in some implementation scenarios, in some situations,and/or in some frequencies no LBT procedure may performed by thetransmitting entity. In an example, Category 2 (e.g. LBT without randomback-off) may be implemented. The duration of time that the channel issensed to be idle before the transmitting entity transmits may bedeterministic. In an example, Category 3 (e.g. LBT with random back-offwith a contention window of fixed size) may be implemented. The LBTprocedure may have the following procedure as one of its components. Thetransmitting entity may draw a random number N within a contentionwindow. The size of the contention window may be specified by theminimum and maximum value of N. The size of the contention window may befixed. The random number N may be employed in the LBT procedure todetermine the duration of time that the channel is sensed to be idlebefore the transmitting entity transmits on the channel. In an example,Category 4 (e.g. LBT with random back-off with a contention window ofvariable size) may be implemented. The transmitting entity may draw arandom number N within a contention window. The size of contentionwindow may be specified by the minimum and maximum value of N. Thetransmitting entity may vary the size of the contention window whendrawing the random number N. The random number N is used in the LBTprocedure to determine the duration of time that the channel is sensedto be idle before the transmitting entity transmits on the channel.

LAA may employ uplink LBT at the UE. The UL LBT scheme may be differentfrom the DL LBT scheme (e.g. by using different LBT mechanisms orparameters) for example, since the LAA UL is based on scheduled accesswhich affects a UE's channel contention opportunities. Otherconsiderations motivating a different UL LBT scheme include, but are notlimited to, multiplexing of multiple UEs in a single subframe.

In an example, a DL transmission burst may be a continuous transmissionfrom a DL transmitting node with no transmission immediately before orafter from the same node on the same CC. An UL transmission burst from aUE perspective may be a continuous transmission from a UE with notransmission immediately before or after from the same UE on the sameCC. In an example, UL transmission burst is defined from a UEperspective. In an example, an UL transmission burst may be defined froman eNB perspective. In an example, in case of an eNB operating DL+UL LAAover the same unlicensed carrier, DL transmission burst(s) and ULtransmission burst(s) on LAA may be scheduled in a TDM manner over thesame unlicensed carrier. For example, an instant in time may be part ofa DL transmission burst or an UL transmission burst.

According to some of the various aspects of embodiments, initial timingalignment may be achieved through a random access procedure. This mayinvolve a UE transmitting at least one random access preamble and anbase station responding with an initial TA command NTA (amount of timingadvance) within a random access response window. The start of the randomaccess preamble may be aligned with the start of a corresponding uplinksubframe at the UE assuming NTA=0. The base station may estimate theuplink timing from the random access preamble transmitted by the UE. TheTA command may be derived by the base station based on the estimation ofthe difference between the desired UL timing and the actual UL timing.The UE may determine the initial uplink transmission timing relative tothe corresponding downlink of a TAG on which the preamble istransmitted. TA value may be determined based on the timing differencebetween a reference downlink signal timing and uplink transmissiontiming. A timing advance value depends at least on channel condition,e.g. propagation delay.

In an example, a wireless device may employ multiple cells served bydifferent transmission/reception points of a base station. One or morecells of the multiple cells may by served by multipletransmission/reception points. In an example, depending on atransmission/reception point serving a cell for a wireless device, atiming advance of the cell for the wireless device may vary when thecell operates with multiple transmission/reception points. In anexample, depending on a transmission/reception point serving a cell fora wireless device, the cell may need to belong to different timingadvance group (TAG) of the wireless device. In an example, propagationdelay and timing advance of a cell may change when a wireless devicemoves in a coverage area and/or connect to a different transmissionpoint.

In existing technologies, if a gNB is split into a gNB-CU and a gNB-DU,a gNB-CU may provide at least an RRC layer and a gNB-DU may provide atleast one of a physical layer and/or a MAC layer. In an example, when atiming advance of a cell changes, a gNB-DU may detect a change of atiming advance value of the cell for the wireless device. A gNB-CU maynot be aware of the change of the timing advance of a cell of a wirelessdevice. A gNB-CU may configure, for a wireless device, RRC parameters(e.g. RRC messages) comprising TAG configuration parameters withoutinformation of a timing advance change of a cell of a wireless device.Implementation of existing RRC message configuration mechanism of agNB-CU may configure inappropriate parameters for the wireless device.The existing technology may decrease radio channel reliability andincrease a interference generated by a wireless device. There is a needto develop enhance signaling mechanisms among a gNB-CU, a gNB-DU and awireless device so that a gNB-CU can properly configure timing advancegroups to enhance uplink timing and reduce interference.

Example embodiments enhance RRC parameter configuration mechanisms of agNB-CU when a gNB-DU provides lower layer functions of a gNB. Exampleembodiments may enhance interactions of a gNB-CU and a gNB-DU toconfigure timing alignment configuration parameters for wirelessdevices. Example embodiments may increase connection reliability anddecrease interference of wireless devices by enhancing parameterconfiguration mechanisms of a gNB-CU and a gNB-DU for wireless devices.

In an example embodiment, a base station may comprise a gNB, eNB, anRNC, a home eNB, a home gNB, NG-eNB, Integrated Access and Backhaul(IAB) node, a relay node, an access point and/or any type of basestations or access points communicating with one or more wirelessdevices. Example embodiments for an example base station may be appliedto other types of base stations. For example an embodiment on gNB can beapplied to implementation of IAB node. In an example embodiment, agNB-CU may be interpreted as a centralized base station (e.g. eNB-CU,RNC, access point central unit, relay donor node, integrated access andbackhaul (IAB) donor node, and/or the like). In an example embodiment, agNB-DU may be interpreted as a distributed base station (e.g. eNB-DU,RRH, transmission and reception point (TRP), access point distributedunit, relay node, IAB) node, and/or the like).

In an example embodiment, an uplink timing advance (TA) associated witha first cell may be changed when a wireless device moves from a firsttransmission point to a second transmission point of the first cell. Inan example, if both the first cell and a second cell belong to a firsttiming advance group (TAG) for the wireless device and the second cellis not served by the second transmission point, the first cell and thesecond cell may not be able to belong to the same TAG (e.g. the firstTAG) when the wireless device moves to the second transmission point forthe first cell because an uplink TA associated with the second cell maynot be changed. In an example, a base station may update a TAG for thefirst cell and/or the second cell in response to a TA change of thefirst cell. In an example, the base station may assign different TAGsfor the first cell and the second cell at the time of allocating thefirst cell and the second cell to the wireless device if the basestation has information of TA correlation information between differentcells.

In an example, a base station may comprise a central RAN entity (e.g.gNB-CU) and one or more distributed RAN entities (e.g. gNB-DUs). Adistributed RAN entity of the one or more distributed RAN entity mayserve at least one cell. The central RAN entity may provide at least aradio resource control (RRC) functionality and/or a packet dataconvergence protocol (PDCP) layer functionality. The distributed RANentity may provide at least a radio link control (RLC) layerfunctionality, a medium access control (MAC) layer functionality, and/ora physical (PHY) layer functionality.

An F1 interface (e.g. a logical direct interface) may be setup betweenthe central RAN entity and the distributed RAN entity. The F1 interfacemay comprise a user plane interface and/or a control plane interface.RRC messages may be transmitted from the central RAN entity to awireless device or from a wireless device to the central RAN entity viathe distributed RAN entity. Data packets may be transmitted from thecentral RAN entity to a wireless device or from a wireless device to thecentral RAN entity via the distributed RAN entity. In an example, datapackets transmitted over the F1 interface may be PDCP layer packets. Inan example, RRC messages transmitted over the F1 interface may beconveyed by an F1 interface message, and/or the RRC messages conveyed bythe F1 interface message may be one or more PDCP layer packetsassociated with one or more signaling radio bearers.

In an example embodiment, as shown in FIG. 15 and FIG. 16, a distributedradio access network (RAN) entity may receive, from a wireless device,one or more first reference signals (e.g. a sounding reference signal,SRS, a random access preamble, and/or the like) via a first cell and oneor more second reference signals via a second cell. The first cell andthe second cell may be configured to belong to the same timing advancegroup (TAG), a first TAG. The configuration of the first TAG may be setby the distributed RAN entity and/or by a central RAN entitycorresponding to the distributed RAN entity. In an example, thedistributed RAN entity may configure the first cell and the second cellas the first TAG, and/or may transmit the configuration information ofthe first TAG to the central RAN entity via an F1 interface and/or tothe wireless device via a radio interface (e.g. a medium access controllayer, a physical layer, and/or the like). In an example, a central RANentity may configure the first cell and the second cell as the firstTAG, and/or may transmit the configuration information of the first TAGto the distributed RAN entity via an F1 interface and/or to the wirelessdevice via one or more radio resource control (RRC) layer messages.

In an example, in response to receiving the one or more first referencesignals, the distributed RAN entity may measure a first uplink timingadvance (TA) value for the first cell based on at least one of the oneor more first reference signals. In response to receiving the one ormore second reference signals, the distributed RAN entity may measure asecond uplink TA value for the second cell based on at least one of theone or more second reference signals. The distributed RAN entity maydetermine whether the first uplink TA value and the second uplink TAvalue are different each other. In an example, the distributed RANentity may determine whether a difference between the first uplink TAvalue and the second uplink TA value is larger than a threshold value.

For example, the first cell may be served by a first transmission andreception point (TRP), and the second cell may be served by a first TRPand a second TRP. When a base station (e.g. the central RAN entityand/or the distributed RAN entity) assigns the first TAG for the firstcell and the second cell to serve the wireless device, the base stationmay determine that a TA value for the first cell and a TA value for thesecond cell are same (or a difference between two TA values is lowerthan a threshold value) and may decide to assign the same TAG (the sameTAG identifier), the first TAG. In an example, a base stationdistributed unit may determine that a first uplink timing advance valuefor a first cell of a wireless device is same (e.g. a timing differenceis below than a threshold, e.g. 10 micro seconds) as a second uplinktiming advance value for a second cell of the wireless device, whereinthe first cell and the second cell belong to different timing advancegroups.

If the wireless moves to a service area of the second TRP, the firstcell for the wireless device may be served via the first TRP and thesecond cell for the wireless device may be served via the second TRP. Ifa TA value for the first cell and a TA value for the second cell aredifferent each other because serving TRPs for two cells are different,the first cell and the second cell may not be able to belong to the sameTAG. To reconfigure TAG(s) for the first cell and/or the second cell,the distributed RAN entity may need to inform this to the central RANentity.

In an example, if the first uplink TA value and the second uplink TAvalue are different each other and/or if a difference between the firstuplink TA value and the second uplink TA value is larger than athreshold value, the distributed RAN entity may transmit a first messageto the central RAN entity. The first message may be transmitted via anF1 interface between the distributed RAN entity and the central RANentity. The first message may indicate that, for the wireless device, aTA value associated with the first cell and a TA value associated withthe second cell are different each other (e.g. at least the differencebetween two TA values is larger than the threshold value). In anexample, the first message may comprise the first uplink TA value and/orthe second uplink TA value. The first and/or second uplink TA values maycomprise an index value (e.g. 0, 1, 2, . . . , 63), which indicates anamount of time to be adjusted for uplink timing synchronization (timingadvance) for the first cell and/or the second cell. A length of thefirst and/or second uplink TA values may be 6 bits. In an example, thefirst message may comprise an amount of difference between a TA valuefor the first cell and a TA value for the second cell. A value of theamount of difference may comprise an index value (e.g. 0, 1, 2, . . . ,63).

In an example, the first message may indicate a request forreconfiguring a TAG(s) associated with the first cell and/or the secondcell, wherein the request may be one of one or more cell configurationchange requests for the first cell and/or the second cell. In anexample, the first message may indicate, explicitly and/or implicitly,that the first cell and the second cell cannot belong to the same TAGfor the wireless device. In an example, the first message may indicatethat the first cell and the second cell belong to the different TAGs toeach other for the wireless device. In an example, the first message maycomprise one or more reconfiguration information elements indicating areconfiguration of a TAG configuration for the wireless device. In anexample, the first message may further comprise a wireless deviceidentifier of the wireless device (e.g. TMSI, F1 UE identifier, C-RNTI,DU-RNTI, and/or the like).

In an example, the central RAN entity may transmit a response message tothe distributed RAN entity in response to the first message. Theresponse message may be transmitted via the F1 interface between thecentral RAN entity and the distributed RAN entity. The response messagemay indicate an acknowledgement for one or more elements of the firstmessage.

In an example, the central RAN entity may configure the second cell tobelong to a second TAG based on one or more elements of the firstmessage. The central RAN entity may configure the first cell to belongto a second TAG based on one or more elements of the first message. Thecentral RAN entity may configure the first cell and the second cell tobelong to different TAGs each other based on one or more elements of thefirst message. In an example, the central RAN entity may configure asecond message indicating that the first cell and the second cell tobelong to different TAGs each other based on the first message. In anexample, the central RAN entity may configure a second messageindicating that the first cell and the second cell to belong todifferent TAGs each other based on the one or more reconfigurationinformation elements of the first message. In an example, the centralRAN entity may transmit, to the wireless device, the second messagedetermined based on configuring a TAG of the second cell and/or thefirst cell. The second message may be an RRC layer message. In anexample, the second message may be an RRC connection reconfigurationmessage. The second message may indicate that the second cell belongs toa second TAG and/or that the first cell belongs to the first TAG. Thesecond message may indicate that the first cell belongs to a second TAGand/or that the second cell belongs to the first TAG. The second messagemay indicate that the first cell and the second cell belong to differentTAGs each other. In an example, the second message may be transmitted tothe wireless device via the F1 interface and the distributed RAN entity.The distributed RAN entity may forward the second message to thewireless device via a radio interface.

In an example, the second message may comprise a TAG identifierassociated with the second TAG. In an example, the second message maycomprise a TAG identifier of a TAG for the first cell and/or a TAGidentifier of a TAG for the second cell determined based on configuring(updating/reconfiguring) a TAG of the second cell and/or the first cell.

In an example, the distributed RAN entity (e.g. gNB-DU) may interpretthe second message.

In an example, the distributed RAN entity may decode the second message.To transmit the second message to the wireless device, the central RANentity may transmit the second message to the distributed RAN entity viaan F1 interface message by encapsulating the second message into the F1interface message (e.g. via an F1 interface message comprising an RRCcontainer information element, which comprise the second message and/orelements of the second message), and the distributed RAN entity maytransmit (forward) the second message to the wireless device via a radiointerface. By decoding the second message, the distributed RAN entitymay be able to be informed about reconfiguration of a TAG of the firstcell and/or the second cell for the wireless device. In an example, thedistributed RAN entity may transmit, to the wireless device, a timingadvance command (TAC) based on the updated TAGs for the first celland/or the second cell. In an example, the TAC may be transmitted via amedium access control (MAC) control element message.

In an example, the TAC may comprise a TA adjusting value (e.g. 0, 1, 2,. . . , 63) used to control the amount of timing adjustment that a MACentity may apply for uplink transmission. The length of a field for theTAC may be 6 bits.

In an example, the central RAN entity (e.g. gNB-CU) may transmit, to thedistributed RAN entity (e.g. gNB-DU), a message indicating updated TAGconfigurations.

In an example, the central RAN entity may transmit, to the distributedRAN entity, a third message indicating the updated TAG configurationsfor the first cell and/or the second cell, wherein the updated TAGconfigurations may correspond to one or more elements of the secondmessage. The third message may be determined based on the configurationof a TAG of the second cell and/or the first cell at least based on oneor more elements of the first message. The third message may be an F1interface message. The third message may indicate that the second cellbelongs to the second TAG and/or that the first cell belongs to thefirst TAG. The third message may indicate that the first cell belongs tothe second TAG and/or that the second cell belongs to the first TAG. Thethird message may indicate that the first cell and the second cellbelong to different TAGs each other.

In an example, the third message may comprise a TAG identifierassociated with the second TAG. In an example, the third message maycomprise a TAG identifier of a TAG for the first cell and/or a TAGidentifier of a TAG for the second cell determined based on configuring(updating/reconfiguring) a TAG of the second cell and/or the first cell.The third message may further comprise a wireless device identifier ofthe wireless device (e.g. TMSI, F1 UE identifier, C-RNTI, DU-RNTI,and/or the like).

In an example, the distributed RAN entity may transmit, to the wirelessdevice, a timing advance command (TAC) based on the updated TAGs for thefirst cell and/or the second cell at least based on one or more elementsof the third message. In an example, the TAC may be transmitted via amedium access control (MAC) control element message.

In an example, a gNB-CU may receive transmission and reception pointinformation of cells of a gNB-DU.

In an example embodiment, a central radio access network entity (CU,Central Unit) may receive a transmission reception point (TRP)information from a distributed radio access network entity (DU,Distributed Unit) and/or an operation and management (OAM, O&M) entity.The TRP information may comprise one or more beam identifiers of one ormore beams, one or more cell identifiers of one or more cells, and/orone or more TRP identifiers of one or more TRPs. The CU may assign oneor more timing advance groups (TAG) for a wireless device at least basedon one or more elements of the TRP information. In an example, if afirst beam and a second beam are served via the same TRP, the CU mayassign the first beam and the second beam to the same TAG. In anexample, if a first cell and a second cell are served via the same TRP,the CU may assign the first cell and the second cell to the same TAG.The CU may transmit the TAG assignment information associated with oneor more cells and/or one or more beams for the wireless device to thewireless device and/or the DU. The DU may transmit a timing advancecommand to the wireless device at least based on the TAG assignmentinformation received from the CU.

In an example, a distributed RAN entity may transmit, to a central RANentity, a TA correlation information via an F1 interface between thedistribute RAN entity and the central RAN entity. The TA correlationinformation may be transmitted via an F1 setup request message from thedistributed RAN entity to the central RAN entity. The TA correlationinformation may be transmitted via an DU configuration update message(or an DU modification request message) from the distributed RAN entityto the central RAN entity. The TA correlation information may compriseat least one of: at least one identifier of at least one TA correlationgroup (e.g. transmission and reception point, TRP, identifier of atleast one TRP); a list of cells grouped into one of the at least one TAcorrelation group (wherein the list of cells may have the same uplink TAvalue), a list of beams grouped into one of the at least one TAcorrelation group (wherein the list of beams may have the same uplink TAvalue).

In an example, the central RAN entity may configure one or more cellsand/or one or more beams for a wireless device to belong to a first TAGfor the wireless device if the one or more cells and/or the one or morebeams are grouped in the same TA correlation group based on the TAcorrelation information received from the distributed RAN entity or froman operation and management (maintenance) entity (OAM). In an example,the one or more cells and/or the one or more beams may be determined toserve the wireless device at least based on one or more measurementreports from the wireless device and/or radio resource statusinformation.

In an example, the central RAN entity may transmit, to the wirelessdevice, a radio resource control (RRC) configuration informationindicating that a first cell of the one or more cells belongs to thefirst TAG and/or indicating that a first beam of the one or more beamsbelongs to the first TAG based on the configuration. The RRCconfiguration information may be conveyed via an RRC message. The RRCconfiguration information (and/or the RRC message) may be transmittedthrough the distributed RAN entity. The RRC message may indicate, to thewireless device, an addition of the first cell as a secondary celland/or a cell information of the first cell as a handover target cellfor the wireless device. In an example, the RRC message may indicate, tothe wireless device, an addition of the first beam as a serving beam ofa serving cell for the wireless device. The RRC message may comprise anTAG identifier of the first TAG associated the first cell and/or thefirst beam. The RRC message may comprise a cell identifier of the firstcell and/or a beam index (e.g. beam index, synchronization signalinformation, reference signal information associated with the firstbeam) of the first beam.

In an example, the distributed RAN entity may decode the RRCconfiguration information conveyed via the RRC message. The distributedRAN entity may transmit, to the wireless device, a timing advancecommand (TAC) for the first cell and/or the first beam with the TAGidentifier of the first TAG at least based on the RRC configurationinformation.

In an example, the central RAN entity may transmit, to the distributedRAN entity, a configuration update message associated with the wirelessdevice. The configuration update message may indicate the first celland/or the first beam belongs to the first TAG. The configuration updatemessage may comprise the TAG identifier of the first TAG associated thefirst cell and/or the first beam. The configuration update message maycomprise the cell identifier of the first cell and/or the beam index(e.g. beam index, synchronization signal information, reference signalinformation associated with the first beam) of the first beam. In anexample, the distributed RAN entity may transmit, to the wirelessdevice, a timing advance command (TAC) for the first cell and/or thefirst beam with the TAG identifier of the first TAG at least based onthe configuration update message. Example embodiments may increaseconnection reliability and decrease interference of wireless devices byenhancing parameter configuration mechanisms of a gNB-CU and a gNB-DUfor wireless devices.

In an example, the TAC may comprise a TA adjusting value (e.g. 0, 1, 2,. . . , 63) used to control the amount of timing adjustment that a MACentity may apply for uplink transmission. The length of a field for theTAC may be 6 bits.

In an example, a distributed RAN entity may receive, from a wirelessdevice, a first reference signal via a first cell and second referencesignal via a second cell, the first cell and the second cell configuredto belong to a first timing advance group (TAG). The distributed RANentity may determine that a first uplink timing advance (TA) value forthe first cell is different from a second uplink TA value for the secondcell based on the first reference signal and the second referencesignal. The distributed RAN entity may transmit, to a central RANentity, a first message indicating at least one of: the first uplink TAvalue may be different to the second uplink TA value for the wirelessdevice; the first uplink TA value; the second uplink TA value; adifferent value between the first uplink TA value and the second uplinkTA value; a TAG reconfiguration request at least for the second cell orthe first cell; and/or the like.

The distributed RAN entity may receive, from the central RAN entity, aresponse message in response to the first message, the response messagethat may indicate an acknowledgement for one or more elements of thefirst message. In an example, the central RAN entity may configure thesecond cell to belong to a second TAG based on the first message. Thecentral RAN entity may transmit, to the wireless device via thedistributed radio access network entity, a second message indicatingthat the second cell belongs to the second TAG, wherein the secondmessage may comprise a TAG identifier associated with the second TAG.

In an example, the distributed RAN entity may decode the second message,and/or transmit, to the wireless device, a timing advance command forthe second cell with the TAG identifier. In an example, the distributedRAN entity may receive, from the central RAN entity, a third messageindicating that the second cell belongs to the second TAG, wherein thethird message may comprise the TAG identifier. The distributed RANentity may transmit, to the wireless device, a timing advance commandfor the second cell with the TAG identifier.

In an example, a central RAN entity may receive, from a first networkentity, a timing advance (TA) correlation information, the TAcorrelation information comprising at least one of: at least oneidentifier of at least one TA correlation group; and/or a list of cellsgrouped into one of the at least one TA correlation group, the list ofcells that may have the same uplink TA value. The central RAN entity mayconfigure one or more cells for a wireless device to belong to a firsttiming advance group (TAG) for the wireless device if the one or morecells are in the list of cells. The central RAN entity may transmit, tothe wireless device via a distributed RAN entity, a radio resourcecontrol (RRC) configuration information indicating a first cell of theone or more cells belongs to the first TAG, the RRC configurationinformation that may comprise a cell identifier of the first cell and aTAG identifier of the first TAG. In an example, the first network entityis the distributed RAN entity. The first network entity is an operationand maintenance entity.

In an example, the distributed RAN entity may decode the radio resourcecontrol (RRC) configuration information, and/or transmit, to thewireless device, a timing advance command for the first cell with theTAG identifier. In an example, the distributed RAN entity may receive,from the central RAN entity, a first message indicating that the firstcell may belong to the first TAG, wherein the first message may comprisethe TAG identifier. The distributed RAN entity may transmit, to thewireless device, a timing advance command for the first cell with theTAG identifier. Example embodiments may increase connection reliabilityand decrease interference of wireless devices by enhancing parameterconfiguration mechanisms of a gNB-CU and a gNB-DU for wireless devices.

In existing technologies, if a gNB is split into a gNB-CU and a gNB-DU,a gNB-CU may provide at least an RRC layer and a gNB-DU may provide atleast one of a physical layer and/or a MAC layer. A gNB-CU may determineRRC parameters (e.g. RRC messages) and/or perform connection control fora wireless device. gNB-CU may not be maintain a timing alignment timerfor a timing advance group, and may not be aware of expiry of a timingalignment timer. Implementation of existing parameter configurationand/or connection control mechanisms of a gNB-CU may configureinappropriate parameters for the wireless device when a gNB-CU is notaware that a time alignment timer of a timing advance group is expired.For example, gNB-CU may not be able to release uplink resourceconfigurations at a proper time when time alignment timer of a TAGexpires. The existing technology may increase unwanted uplinkinterference and increase a packet transmission/reception failure rateof wireless devices. There is a need to develop enhance signalingmechanisms among a gNB-CU, a gNB-DU and a wireless device so that agNB-CU can properly configure and/or release uplink channels and timingadvance groups to enhance uplink timing and reduce interference.

Example embodiments enhance radio parameter configuration and/orconnection control mechanisms of a gNB-CU when a gNB-DU provides lowerlayer functions of a gNB. Example embodiments may enhance interactionsof a gNB-CU and a gNB-DU to configure radio control parameters and/orconnection control parameters for wireless devices. Example embodimentsmay increase connection reliability and decrease interference byenhancing parameter configuration and/or release by a gNB-CU and agNB-DU for a wireless device.

In an example embodiment, a distributed radio access network (RAN)entity may determine that a time alignment timer (TAT) for a timingadvance group (e.g. primary TAG, pTAG, and/or secondary TAG, sTAG) of awireless device expires. In response to the detection of the TATexpiration for the TAG, the distributed RAN entity may inform the TATexpiration to a central RAN entity. The central RAN entity may releaseone or more configurations associated with the wireless device and/orone or more cells belonging to the TAG based on the information of theTAT expiration.

In an example, a MAC entity may have a configurable timertimeAlignmentTimer (TAT) per TAG. The timeAlignmentTimer may be used tocontrol how long the MAC entity considers the Serving Cells belonging tothe associated TAG to be uplink time aligned.

In an example, the MAC entity, when a Timing Advance Command (TAC) MACcontrol element is received: may apply the Timing Advance Command forthe indicated TAG, and/or may start or restart the timeAlignmentTimerassociated with the indicated TAG.

In an example, the MAC entity, when a Timing Advance Command is receivedin a Random Access Response (RAR) message for a serving cell belongingto a TAG: if the Random Access Preamble was not selected by the MACentity, may apply the Timing Advance Command for this TAG, and/or maystart or restart the timeAlignmentTimer associated with this TAG; elseif the timeAlignmentTimer associated with this TAG is not running, mayapply the Timing Advance Command for this TAG, may start thetimeAlignmentTimer associated with this TAG, and/or, when the contentionresolution is considered not successful, may stop timeAlignmentTimerassociated with this TAG; else may ignore the received Timing AdvanceCommand.

In an example, the MAC entity, when a timeAlignmentTimer expires: if thetimeAlignmentTimer is associated with the pTAG: may flush all HARQbuffers for all serving cells, may notify RRC to release PUCCH for allserving cells, may notify RRC to release SRS for all serving cells, mayclear any configured downlink assignments and uplink grants, and/or mayconsider all running timeAlignmentTimers as expired; else if thetimeAlignmentTimer is associated with an sTAG, then for Serving Cellsbelonging to this TAG: may flush all HARQ buffers, may notify RRC torelease SRS, and/or may notify RRC to release PUCCH, if configured.

In an example, when the MAC entity stops uplink transmissions for anSCell due to the fact that the maximum uplink transmission timingdifference or the maximum uplink transmission timing difference the UEmay handle between TAGs of any MAC entity of the UE is exceeded, the MACentity may consider the timeAlignmentTimer associated with the SCell asexpired.

The MAC entity may not perform an uplink transmission on a Serving Cellexcept the Random Access Preamble transmission when thetimeAlignmentTimer associated with the TAG to which this Serving Cellbelongs is not running. Furthermore, when the timeAlignmentTimerassociated with the pTAG is not running, the MAC entity may not performany uplink transmission on any Serving Cell except the Random AccessPreamble transmission on the SpCell.

The MAC entity may not perform a sidelink transmission which may beperformed based on UL timing of the corresponding serving cell andassociated SCI transmissions when the corresponding timeAlignmentTimermay not be running. A MAC entity may store and/or maintain NTA uponexpiry of associated timeAlignmentTimer, where NTA may be defined. TheMAC entity may apply a received Timing Advance Command MAC controlelement and/or may start associated timeAlignmentTimer also when thetimeAlignmentTimer is not running.

In an example, a base station may comprise a central RAN entity and oneor more distributed RAN entities. A distributed RAN entity of the one ormore distributed RAN entity may serve at least one cell. The central RANentity may provide at least a radio resource control (RRC) functionalityand/or a packet data convergence protocol (PDCP) layer functionality.The distributed RAN entity may provide at least a radio link control(RLC) layer functionality, a medium access control (MAC) layerfunctionality, and/or a physical (PHY) layer functionality.

An F1 interface (e.g. a logical direct interface) may be setup betweenthe central RAN entity and the distributed RAN entity. The F1 interfacemay comprise a user plane interface and/or a control plane interface.RRC messages may be transmitted from the central RAN entity to awireless device or from a wireless device to the central RAN entity viathe distributed RAN entity. Data packets may be transmitted from thecentral RAN entity to a wireless device or from a wireless device to thecentral RAN entity via the distributed RAN entity. In an example, datapackets transmitted over the F1 interface may be PDCP layer packets. Inan example, RRC messages transmitted over the F1 interface may beconveyed by an F1 interface message, and/or the RRC messages conveyed bythe F1 interface message may be one or more PDCP layer packetsassociated with one or more signaling radio bearers.

In an example embodiment, as shown in FIG. 17, a base station comprisinga distributed RAN entity and/or a central RAN entity may assign one ormore cells to a wireless device. The one or more cells may belong to atiming advance group (TAG). The wireless device may transmit and/orreceive packets to/from the base station (e.g. the distributed RANentity and/or the central RAN entity). In an example, the distributedRAN entity may transmit a timing advance command (TAC) for the TAG tothe wireless device. The TAC may be transmitted via a medium accesscontrol (MAC) layer message, e.g. MAC control element (MAC CE) message.In an example, the TAC may be transmitted via a random access responsemessage for a serving cell belonging to the TAG. The TAC may betransmitted with a TAG identifier of the TAG. In an example, the TAC maycomprise a TA adjusting value (e.g. 0, 1, 2, . . . , 63) used to controlthe amount of timing adjustment that a MAC entity may apply. The lengthof a field for the TAC may be 6 bits.

In response to transmitting the TAC to the wireless device, thedistributed RAN entity may start or restart a time alignment timer (TAT)associated with the TAG for the wireless device. The distributed RANentity may determine whether the TAT expires after starting orrestarting the TAT. When the distributed RAN entity does notsuccessfully transmit another TAC to the wireless device within a timeduration of the TAT since the TAT is started and/or restarted, thedistributed RAN entity may determine that the TAT expires.

In an example, the TAT may be configured by the central RAN entity (e.g.an RRC) and/or the distributed RAN entity. The TAT may be transmittedfrom the base station to the wireless device via a RRC message. The TATmay be configured as the number of subframes, e.g. 500 subframes, 750subframes, 1280 subframes, 1920 subframes, 2560 subframes, 5120subframes, 10240 subframes, infinite number of subframes, and/or thelike.

In an example, in response to determining that the TAT associated withthe TAG for the wireless device expires, the distributed RAN entity: mayflush hybrid automated repeat request (HARQ) uplink resources configuredfor the one or more cells; may release physical uplink control channel(PUCCH) configurations for the one or more cells; may release soundingreference signal (SRS) configurations for the one or more cells; mayclear configured downlink assignments for the one or more cells; mayclear uplink resource grants for the one or more cells; may consider allrunning TAT as expired if the TAG is a primary TAG; and/or the like.

In an example, in response to the TAT expiration, the distributed RANentity may release HARQ uplink resources configured on the one or morecells for the wireless device. The distributed RAN entity may releasePUCCH radio resources configured on the one or more cells for thewireless device. The distributed RAN entity may release SRS radioresources configured on the one or more cells for the wireless device.The distributed RAN entity may clear downlink radio resource assignmentsconfigured for periodic downlink packet transmissions via the one ormore cells. The distributed RAN entity may clear uplink resource grantsconfigured for uplink packet transmissions via the one or more cells. Incase that the TAG is a primary TAG of the wireless device, thedistributed RAN entity may consider running TATs for secondary TAGs asexpired, and/or may release uplink HARQ resource configurations, PUCCHconfigurations, SRS configurations, downlink resource assignments and/oruplink granted resource configurations for one or more cells of thesecondary TAGs.

In an example, in response to the TAT expiration, the distributed RANentity may apply default physical channel configurations for the one ormore cells of the TAG. The default channel configurations may beconfigured for at least one of channel quality information (CQI) reportconfigurations, uplink resource scheduling request configurations,dedicated uplink SRS configurations, and/or the like.

In an example, in response to determining that the TAT associated withthe TAG for the wireless device expires, the distributed RAN entity maytransmit a first message to the central RAN entity. The first messagemay be transmitted via an F1 interface between the central RAN entityand the distributed RAN entity. The first message may comprise awireless device identifier of the wireless device, at least one cellidentifier of one or more cell identifiers of the one or more cellbelonging to the TAG, a TAG identifier of the TAG, and/or the like. Inan example, the first message may indicate that the TAT associated withthe TAG for the wireless device expired.

In an example, the first message may comprise at least one notificationsfor at least one of: releasing hybrid automated repeat request (HARQ)uplink resource configurations for the one or more cells, a releasingphysical uplink control channel (PUCCH) configurations for the one ormore cells, releasing a sounding reference signal (SRS) configurationsfor the one or more cells, clearing configured downlink assignments forthe one or more cells, clearing uplink resource grants for the one ormore cells, considering all running TAT as expired if the TAG is aprimary TAG, and/or the like.

In an example, if the central RAN entity receives the first message, thecentral RAN entity may perform at least one of the following: may flushhybrid automated repeat request (HARQ) uplink resources configured forthe one or more cells; may release physical uplink control channel(PUCCH) configurations for the one or more cells; may release soundingreference signal (SRS) configurations for the one or more cells; mayclear configured downlink assignments for the one or more cells; mayclear uplink resource grants for the one or more cells; may consider allrunning TAT as expired if the TAG is a primary TAG; and/or the like.Example embodiments may increase connection reliability and decreaseinterference by enhancing parameter configuration and/or release by agNB-CU and a gNB-DU for a wireless device.

In an example, in response to receiving the first message, the centralRAN entity may release HARQ uplink resource configurations on the one ormore cells for the wireless device. The central RAN entity may releasePUCCH radio resource configurations for the one or more cells for thewireless device. The central RAN entity may release SRS radio resourceconfigurations for the one or more cells for the wireless device. Thecentral RAN entity may clear downlink radio resource assignmentconfigurations for periodic downlink packet transmissions via the one ormore cells for the wireless device. The central RAN entity may clearuplink resource grant configurations for uplink packet transmissions viathe one or more cells for the wireless device. In case that the TAG is aprimary TAG of the wireless device, the central RAN entity may considerrunning TATs for secondary TAGs as expired, and/or the like.

In an example, in response to receiving the first message, the centralRAN entity may apply default physical channel configurations for the oneor more cells of the TAG. The default channel configurations may beconfigured for at least one of channel quality information (CQI) reportconfigurations, uplink resource scheduling request configurations,dedicated uplink SRS configurations, and/or the like.

In an example, in response to one or more elements of the first message,the central RAN entity may transmit, to the distributed RAN entity, asecond message indicating a first wireless device context releaserequest for the wireless device. The second message may be transmittedvia the F1 interface. The second message may be a UE context releasecommand message. The second message may be transmitted when the TAGassociated with the TAT expiration is a primary TAG for the wirelessdevice. In an example, a first wireless device context released at leastbased on the second message may comprise one or more data radio bearers,one or more logical channels, one or more security configurationparameters, one or more information, and/or the like configurationsassociated with the wireless device.

In an example, in response to one or more elements of the first message,the central RAN entity may transmit, to a core network entity (e.g. AMF,MME, and/or the like), a third message indicating a second wirelessdevice context release request for the wireless device, wherein thesecond wireless device context release request may be at leastassociated with an interface connection between the central RAN entityand the core network entity for the wireless device. The third messagemay be transmitted via a NG interface (i.e. an interface between thecentral RAN entity and the core network entity). The third message maybe a UE context release request message. The third message may betransmitted when the TAG associated with the TAT expiration is a primaryTAG for the wireless device.

In an example, as shown in FIG. 18, a distributed RAN entity maytransmit, to a wireless device, a timing advance command (TAC) for atiming advance group (TAG) comprising one or more cells. The distributedRAN entity may start a time alignment timer (TAT) associated with theTAG for the wireless device. The distributed RAN entity may transmit, toa central RAN entity, a first message associated with the wirelessdevice when the TAT expires.

The first message may indicate at least one of: expiration of the TATassociated with the TAG; a notification to release hybrid automatedrepeat request (HARD) uplink resource configurations for the one or morecells; a notification to release physical uplink control channel (PUCCH)configurations for the one or more cells; a notification to release asounding reference signal (SRS) configurations for the one or morecells; a notification to clear configured downlink assignments for theone or more cells; a notification to clear uplink resource grants forthe one or more cells; a notification to consider all running TAT asexpired if the TAG is a primary TAG; and/or the like. Exampleembodiments may increase connection reliability and decreaseinterference by enhancing parameter configuration and/or release by agNB-CU and a gNB-DU for a wireless device.

In an example, the central RAN entity may apply, for the one or morecells in response to the first message, a default physical channelconfiguration for at least one of: channel quality information (CQI)report configurations; uplink resource scheduling requestconfigurations; dedicated uplink SRS configurations; and/or the like. Inan example, the distributed RAN entity may receive, from the central RANentity, a second message indicating a first wireless device contextrelease request for the wireless device. The first wireless devicecontext release request may be configured at least based on the firstmessage. The central radio access network entity may transmit, to a corenetwork entity, a third message indicating a second wireless devicecontext release request for the wireless device at least based on thefirst message. The second wireless device context release request may beat least associated with an interface connection between the centralradio access network entity and the core network entity for the wirelessdevice.

In an example, the central RAN entity and/or the distributed RAN entitymay release a wireless device context for the wireless device inresponse to the first wireless device context release request. Thewireless device context may comprise one or more data radio bearers; oneor more logical channels; one or more security configuration parameters;one or more information associated with the wireless device; and/or thelike.

In an example, when a gNB is split into a gNB-CU and a gNB-DU, a gNB-CUmay provide at least an RRC layer. A gNB-DU may provide at least one ofa physical layer and/or a MAC layer. In existing technologies, thegNB-DU may not process the RRC configuration parameters. The gNB-DU maybe transparently transmit the RRC configuration parameters. In anexample, a gNB-DU may determine lower layer configuration parameters ofa wireless device. A gNB-CU may determine upper layer configurationparameters. A gNB-CU may transmit RRC configuration parameters (e.g.lower layer and/or upper layer configuration parameters) to a wirelessdevice via gNB-DU. The gNB-DU is unaware of a delivery timing ofconfiguration parameters to the wireless device. The wireless device maytransmit a confirmation message to the gNB-DU confirming the RRCconfiguration parameters. The gNB-DU may not process the confirmation.The gNB-DU may be transparently transmit the confirmation.

In existing technologies, since a gNB-DU transparently communicates RRCmessages, a gNB-DU may not be aware when the wireless device implementsthe configuration parameters and is ready for communication with thegNB-DU using the configuration parameters. This creates timing delays ingNB-DU and wireless device. Implementation of existing parameterconfiguration and/or application mechanisms of a gNB-DU may increasemisaligned parameter configurations for wireless devices. This mayadditionally cause unsynchronized behavior between gNB-DU and UE. Thereis a need to enhance signaling between gNB-DU, gNB-CU and the wirelessdevice to improve implementation of configuration parameters. Exampleembodiments introduces one or more signaling messages to resolve thisissue. Example embodiments enhances implementation of RRC configurationparameters.

In an example embodiment, a central radio access network (RAN) entitymay transmit a radio resource control (RRC) message to a wireless devicevia a distributed RAN entity. The RRC message may comprise one or moreradio resource configuration parameters associated with one or morecells serving the wireless device, the one or more cells served by thedistributed RAN entity. The one or more radio resource configurationparameters may be associated with one or more configurations in thedistributed RAN entity. To apply the one or more configurations for thewireless device, the distributed RAN entity may need to confirm that theone or more radio resource configuration parameters associated with theone or more configurations have been transmitted to the wireless deviceand/or have been complied by the wireless device. In an example, thedistributed RAN entity may make this confirmation by decoding the RRCmessage transmitted by the central RAN entity to the wireless device viathe distributed RAN entity. In an example, the distributed RAN entitymay make this confirmation by receiving a confirmation message from thecentral RAN entity, the confirmation message transmitted at least basedon a response message for the RRC message from the wireless device tothe central RAN entity.

In an example, the distributed RAN entity may make this confirmation byreceiving an RRC configuration index via an F1 message conveying the RRCmessage and/or via an RRC response message of the RRC message from thewireless device, wherein the RRC configuration index may be exchangedbetween the distributed RAN entity and the central RAN entity whenconfiguring the one or more radio resource configuration parameters.

In an example, the distributed RAN entity may make this confirmation bystarting an RRC timer after forwarding the RRC message to the wirelessdevice. If the RRC timer expires, the distributed RAN entity mayconsider the one or more radio resource configuration parameters may (ormay not) be complied by the wireless device. In an example, if thedistributed RAN entity receives an RRC response message for the RRCmessage before the RRC timer expires, the distributed RAN entity mayconsider the one or more radio resource configuration parameters may becomplied by the wireless device.

In an example, the distributed RAN entity may make this confirmation byreceiving an RRC configuration confirmation message for the one or moreradio resource configuration parameters of the RRC message from thewireless device. The RRC configuration message may indicate that thewireless device complies the one or more radio resource configurationparameters. The RRC configuration message may be transmitted via amedium access control (MAC) control element and/or a physical layerindication.

In an example, a base station may comprise a central RAN entity and oneor more distributed RAN entities. A distributed RAN entity of the one ormore distributed RAN entity may serve at least one cell. The central RANentity may provide at least a radio resource control (RRC) functionalityand/or a packet data convergence protocol (PDCP) layer functionality.The distributed RAN entity may provide at least a radio link control(RLC) layer functionality, a medium access control (MAC) layerfunctionality, and/or a physical (PHY) layer functionality.

An F1 interface (e.g. a logical direct interface) may be setup betweenthe central RAN entity and the distributed RAN entity. The F1 interfacemay comprise a user plane interface and/or a control plane interface.RRC messages may be transmitted from the central RAN entity to awireless device or from a wireless device to the central RAN entity viathe distributed RAN entity. Data packets may be transmitted from thecentral RAN entity to a wireless device or from a wireless device to thecentral RAN entity via the distributed RAN entity. In an example, datapackets transmitted over the F1 interface may be PDCP layer packets. Inan example, RRC messages transmitted over the F1 interface may beconveyed by an F1 interface message, and/or the RRC messages conveyed bythe F1 interface message may be one or more PDCP layer packetsassociated with one or more signaling radio bearers.

In an example embodiment, as shown in FIG. 20, a wireless device may beserved by a base station comprising a central RAN entity and adistributed RAN entity. The distributed RAN entity of the base stationmay serve the wireless device with one or more serving cells. Thedistributed RAN entity and the central RAN entity may be connected via aF1 interface, which may be employed for data transmission and/or controlmessage transmission.

In an example, the central RAN entity may transmit, to the distributedRAN entity, a first message comprising a radio resource configurationinformation associated with a first cell for the wireless device. Thefirst cell may be one of the one or more serving cells served by thedistributed RAN entity. The first message may be transmitted via the F1interface. In an example, the radio resource configuration informationmay be a request for a cell activation/deactivation, cellconfigurations, radio resource configurations, radio transmission powerconfigurations, sidelink communication configurations, and/or the likeconfigurations of the distributed RAN entity and/or the first cell. Theradio resource configuration information may be associated with thewireless device. In an example, the radio resource configurationinformation may comprise configuration parameters determined by thecentral RAN entity, and/or configuration request for configurationsdetermined by the distributed RAN entity.

In an example, if the radio resource configuration information comprisesa cell activation request of the first cell for the wireless device, theradio resource configuration information may comprise a request of cellactivation and/or configuration parameters associated with the cellactivation, e.g. a random access (RA) information for the wirelessdevice (e.g. a preamble index, an RA resource scheduling).

In an example, if the radio resource configuration information is for aperiodic resource assignment for the wireless device on the first cell(e.g. semi-persistent scheduling, grant free resource scheduling, and/orthe like), the radio resource configuration information may comprise arequest indication of periodic resource assignment and/or configurationparameters associated with the periodic resource assignment, e.g. aperiodic resource scheduling information (e.g. semi-persistentscheduling, grant free resource scheduling, and/or the like) such as aperiodicity, resource frequency information, resource block indicator,subframe indicator, TTI (numerology) indicator, and/or the like.

In an example, if the radio resource configuration information is for asidelink communication of the wireless device with other wireless devicein at least the first cell, the radio resource configuration informationmay comprise a request for sidelink resource configurations and/orconfiguration parameters associated with the sidelink resourcescheduling.

In an example, the distributed RAN entity may transmit, to the centralRAN entity, a second message in response to the first message. Thesecond message may be based on one or more elements of the firstmessage. The second message may be a response message to one or morerequests indicated in the first message. The second message may betransmitted via the F1 interface. In an example, the second message maycomprise an acknowledge of one or more requests and/or suggestedconfigurations from the central RAN entity in the first message. Thedistributed RAN entity may apply one or more configurations suggested inthe first message and/or apply configurations requested in the firstmessage for the wireless device and/or the first cell. In an example,the second message may be an acknowledge of a cellactivation/deactivation, cell configurations, radio resourceconfigurations, radio transmission power configurations, sidelinkcommunication configurations, and/or the like configurations of thedistributed RAN entity and/or the first cell.

In an example, the second message may be associated with the wirelessdevice. The second message may comprise configuration parameters, forthe first cell and/or the wireless device, applied in the distributedRAN entity (e.g. for the first cell, other serving cells, and/or thewireless device) and/or determined by the distributed RAN entity atleast based on the first message. The second message may comprise anacknowledge indicating that one or more configuration parameters in thefirst message are applied at least to the first cell and/or the wirelessdevice configurations.

In an example, if the second message comprises a cell activationindication of the first cell for the wireless device, the second messagemay comprise an indication of cell activation and/or configurationparameters (applied and/or to be applied to the first cell and/or thewireless device) associated with the cell activation, e.g. a randomaccess (RA) information for the wireless device (e.g. a preamble index,an RA resource scheduling).

In an example, if the second message is for a periodic resourceassignment indication for the wireless device on the first cell (e.g.semi-persistent scheduling, grant free resource scheduling, and/or thelike), the second message may comprise a acknowledge indication ofperiodic resource assignment and/or configuration parameters (appliedand/or to be applied to the first cell and/or the wireless device)associated with the periodic resource assignment, e.g. a periodicresource scheduling information (e.g. semi-persistent scheduling, grantfree resource scheduling, and/or the like) such as a periodicity,resource frequency information, resource block indicator, subframeindicator, TTI (numerology) indicator, and/or the like.

In an example, if the second message is for a sidelink communication ofthe wireless device with other wireless device in at least the firstcell, the second message may comprise an acknowledge indication forsidelink resource configurations and/or configuration parameters(applied and/or to be applied to the first cell and/or the wirelessdevice) associated with the sidelink resource scheduling.

In an example, the central RAN entity may transmit, to the wirelessdevice, a third message configured at least based on one or moreelements of the second message. The third message may be a radioresource control (RRC) message. The third message may be transmitted viathe F1 interface to the distributed RAN entity, and the distributed RANentity may forward the third message to the wireless device via a radiointerface (e.g. Uu interface). The third message may comprise an RRCconfiguration information associated with one or more elements of theradio resource configuration information of the first message and/or oneor more elements of the second message. The RRC configurationinformation may be determined at least based on one or more elements ofthe second message, e.g. the configuration parameters applied in thedistributed RAN entity determined by the distributed RAN entity for thefirst cell, other serving cells, and/or the wireless device. The RRCconfiguration information may be determined at least based on theacknowledge indicating that one or more configuration parameters in thefirst message are applied at least to the first cell and/or the wirelessdevice configurations.

In an example, the RRC configuration information may comprise one ormore configuration parameters and/or indications for a cellactivation/deactivation, cell configurations, radio resourceconfigurations, radio transmission power configurations, sidelinkcommunication configurations, and/or the like configurations of thedistributed RAN entity and/or the first cell.

In an example, if the RRC configuration information comprises a celladdition/modification indication of the first cell for the wirelessdevice, the RRC configuration information may comprise an indication ofcell addition and/or configuration parameters associated with the celladdition of the first cell, e.g. a random access (RA) information forthe wireless device (e.g. a preamble index, an RA resource scheduling),cell frequency information, one or more beam indexes for one or morebeams of the first cell, and/or the like.

In an example, if the RRC configuration information is for a periodicresource assignment for the wireless device on the first cell (e.g.semi-persistent scheduling, grant free resource scheduling, and/or thelike), the RRC configuration information may comprise an indication ofperiodic resource assignment and/or configuration parameters associatedwith the periodic resource assignment, e.g. a periodic resourcescheduling information (e.g. semi-persistent scheduling information,grant free resource scheduling information, and/or the like) such as aperiodicity, resource frequency information, resource block indicator,subframe indicator, TTI (numerology) indicator, and/or the like.

In an example, if the RRC configuration information is for a sidelinkcommunication of the wireless device with other wireless device in atleast the first cell, the RRC configuration information may comprise anindication for sidelink resource configurations and/or configurationparameters associated with the sidelink resource scheduling on the firstcell.

In an example, the wireless device may transmit, to the central RANentity in response to the third message, a fourth message confirming oneor more elements of the RRC configuration information of the thirdmessage. In an example, the fourth message may be an RRC message. Thefourth message may be transmitted to the distributed RAN entity via aradio interface (e.g. Uu interface), and the distributed RAN entity mayforward the fourth message to the central RAN entity via the F1interface. In an example, the fourth message may indicate one or moreacknowledges for one or more elements of the third message.

In an example, as shown in FIG. 21 a gNB-DU may decode one or more RRCmessages transmitted between a gNB-CU and a wireless device to determinethat a wireless device receives (and/or applies) RRC configurations.

In an example, the distributed RAN entity may decode the third message(e.g. the RRC message transmitted to the wireless device). The thirdmessage may be transmitted via the F1 interface to the distributed RANentity, and the distributed RAN entity may forward the third message tothe wireless device. In an example, when the central RAN entitytransmits the third message to the distributed RAN entity, the centralRAN entity may transmit it with an indication indicating that thedistributed RAN entity needs to decode the third message. In an example,the third message and/or the indication may be conveyed through an F1message from the central RAN entity to the distributed RAN entity. TheF1 message may comprise at least one of the third message, theindication, a wireless device identifier (e.g. UE ID) of the wirelessdevice, and/or the like. In an example, the F1 message may be an RRCtransfer message. The indication may indicates that the third message(i.e. an RRC message transmitted to the wireless device) comprises atleast one element necessary to the distributed RAN entity. In anexample, the distributed RAN entity may decode the third message withoutthe indication in the F1 message.

In an example, the distributed RAN entity may transmit, to the wirelessdevice, a control message associated with the radio resourceconfiguration information of the first message at least based on thedecoding of the third message. The control message may indicate, to thewireless device, an activation of one or more configurations configuredbased on the radio resource configuration information of the firstmessage. In an example, the control message may indicate a cellactivation/deactivation, cell configuration activation, radio resourceconfiguration activation, periodic radio resource configurationactivation (e.g. semi-persistent scheduling resource activation, grantfree resource activation, and/or the like), radio transmission powerconfiguration activation, sidelink communication configurationactivation, and/or the like configuration activation for the distributedRAN entity, the wireless device, and/or the first cell. In an example,the control message may be transmitted via a medium access control (MAC)layer message (e.g. MAC control element), a physical layer message (e.g.physical downlink control channel (PDCCH) order, DCI), and/or the like.

In an example, the distributed RAN entity may decode the fourth message(e.g. the RRC message transmitted by the wireless device to the centralRAN entity). The fourth message may be transmitted via a radio interfacefrom the wireless device to the distributed RAN entity, and thedistributed RAN entity may forward the fourth message to the central RANentity. In an example, when the wireless device transmits the fourthmessage to the distributed RAN entity, the wireless device may transmitit with an indication indicating that the distributed RAN entity needsto decode the fourth message. In an example, the fourth message and/orthe indication may be conveyed through a radio interface message fromthe wireless device to the distributed RAN entity. The radio interfacemessage may comprise at least one of the fourth message, the indication,a wireless device identifier (e.g. UE ID) of the wireless device, and/orthe like. In an example, the radio interface message may be an RRCtransfer message. The indication may indicates that the fourth message(i.e. a radio interface message of the wireless device) comprises atleast one element necessary to the distributed RAN entity. In anexample, the distributed RAN entity may decode the fourth messagewithout the indication in the radio interface message.

In an example, the distributed RAN entity may transmit, to the wirelessdevice, a control message associated with the radio resourceconfiguration information of the first message at least based on thedecoding of the fourth message. The control message may indicate, to thewireless device, an activation of one or more configurations configuredbased on the radio resource configuration information of the firstmessage and/or the second message. In an example, the control messagemay indicate a cell activation/deactivation, cell configurationactivation, radio resource configuration activation, periodic radioresource configuration activation (e.g. semi-persistent schedulingresource activation, grant free resource activation, and/or the like),radio transmission power configuration activation, sidelinkcommunication configuration activation, and/or the like configurationactivation for the distributed RAN entity, the wireless device, and/orthe first cell. In an example, the control message may be transmittedvia a medium access control (MAC) layer message (e.g. MAC controlelement), a physical layer message (e.g. physical downlink controlchannel (PDCCH) order, DCI), and/or the like.

In an example, as shown in FIG. 19 and/or FIG. 22, a gNB-CU (e.g. CU,central unit, central RAN entity) may transmit, to a gNB-DU (e.g. DU,distributed unit, distributed RAN entity) a configuration confirmationmessage indicating that a wireless device receives (and/or applies) RRCconfigurations. The gNB-CU may transmit, to the gNB-DU the configurationconfirmation message in response to receiving the confirmation messagefrom the UE. Example embodiments enhances implementation of RRCconfiguration parameters. With implementation of example embodiments, anadditional message is introduced to align implementation of RRCconfiguration parameters among a gNB-CU, a gNB DU, and a wirelessdevice.

In an example, the central RAN entity may transmit, to the distributedRAN entity, a fifth message indicating that the wireless device compliesone or more configurations associated with one or more elements of theradio resource configuration information in the first message. The fifthmessage may be configured at least based on the third messagetransmission and/or the fourth message reception of the central RANentity. The fifth message may be transmitted via the F1 interface. In anexample, the fifth message may comprise an F1 interface message. In anexample, the fifth message may comprise a UE context modificationrequest message. In an example, the fifth message may comprise acomplete indication information element (IE) indicating that thewireless device completed one or more configurations of one or moreelements of the radio resource configuration information of the firstmessage. In an example, the complete indication IE may comprise an RRCreconfiguration complete indicator IE informing the distributed RANentity (e.g. gNB-DU) that a configuration procedure for the RRCconfiguration information was successfully performed by the wirelessdevice.

In an example, the first message, the second message, and/or the fifthmessage may comprise an RRC configuration index. Based on the RRCconfiguration index, the distributed RAN entity may recognize that thefifth message is a confirmation of one or more configurations in theradio resource configuration information associated with the firstmessage and/or the second message.

In an example, the distributed RAN entity may transmit, to the wirelessdevice, a control message associated with the radio resourceconfiguration information of the first message at least based on thefifth message received from the central RAN entity. The control messagemay indicate, to the wireless device, an activation of one or moreconfigurations configured based on the radio resource configurationinformation of the first message and/or the second message. In anexample, the control message may indicate a cellactivation/deactivation, cell configuration activation, radio resourceconfiguration activation, periodic radio resource configurationactivation (e.g. semi-persistent scheduling resource activation, grantfree resource activation, and/or the like), radio transmission powerconfiguration activation, sidelink communication configurationactivation, and/or the like configuration activation for the distributedRAN entity, the wireless device, and/or the first cell. In an example,the control message may be transmitted via a medium access control (MAC)layer message (e.g. MAC control element), a physical layer message (e.g.physical downlink control channel (PDCCH) order, DCI), and/or the like.

In an example, as shown in FIG. 23, messages for an RRC parameterconfiguration procedure may comprise an RRC configuration index toidentify (and/or distinguish) the RRC parameter configuration procedure.

In an example, the first message and/or the second message may furthercomprise an RRC configuration index. The RRC configuration index may beassociated with the radio resource configuration information in thefirst message and/or the second message. In an example, whentransmitting the third message, the central RAN entity may transmit, tothe distributed RAN entity, the RRC configuration index via the F1interface by adding the RRC configuration index to an F1 messageconveying the third message (i.e. an RRC message). The distributed RANentity may determine, based on the RRC configuration index, that theradio resource configuration information is transmitted to the wirelessdevice.

In an example, when transmitting the fourth message, the wireless devicemay transmit, to the distributed RAN entity, the RRC configuration indexvia a radio interface (e.g. signaling radio bearer) by adding the RRCconfiguration index to at least one packet (e.g. PDCP packet and/or PDCPpacket header) conveying the fourth message (i.e. an RRC message). Thedistributed RAN entity may determine, based on=the RRC configurationindex, that the wireless device receives and/or complies the radioresource configuration information.

In an example, the distributed RAN entity may transmit, to the wirelessdevice, a control message associated with the radio resourceconfiguration information of the first message at least based on the RRCconfiguration index received from the central RAN entity via the F1index and/or received from the wireless device via the radio interface.The control message may indicate, to the wireless device, an activationof one or more configurations configured based on the radio resourceconfiguration information of the first message and/or the secondmessage. In an example, the control message may indicate a cellactivation/deactivation, cell configuration activation, radio resourceconfiguration activation, periodic radio resource configurationactivation (e.g. semi-persistent scheduling resource activation, grantfree resource activation, and/or the like), radio transmission powerconfiguration activation, sidelink communication configurationactivation, and/or the like configuration activation for the distributedRAN entity, the wireless device, and/or the first cell. In an example,the control message may be transmitted via a medium access control (MAC)layer message (e.g. MAC control element), a physical layer message (e.g.physical downlink control channel (PDCCH) order, DCI), and/or the like.

In an example, as shown in FIG. 24, a gNB-DU (e.g. DU, distributed unit,distributed RAN entity) may determine that a wireless device receives(and/or applies) RRC configurations based on an RRC timer.

In an example, the distributed RAN entity may start an RRC timer whenforwarding the third message to the wireless device. In an example, thefirst message, the second message, and/or an F1 message conveying thethird message via the F1 message may comprise an RRC configurationindex. Based on the RRC configuration index, the distributed RAN entitymay recognize that the third message is an RRC message associated withthe radio resource configuration information of the first message and/orthe second message. The RRC timer may start based on the RRCconfiguration index when forwarding the third message. In an example, ifthe RRC timer expires, the distributed RAN entity may consider the radioresource configuration information may be complied by the wirelessdevice.

In an example, if the RRC timer expires, the distributed RAN entity mayconsider the radio resource configuration information may not becomplied by the wireless device, and/or if the distributed RAN entityreceives an RRC response message (which may be transmitted with the RRCconfiguration index) for the RRC message before the RRC timer expires,the distributed RAN entity may consider the radio resource configurationinformation may be complied by the wireless device.

In an example, the RRC timer may be associated with a processing delayrequirement for RRC procedures. The RRC timer may be set to be same toor longer than the processing delay requirement.

In an example, if the distributed RAN entity considers that the wirelessdevice complies at least one of the radio resource configurationinformation based on the RRC timer expiration and/or the RRC responsemessage before the RRC timer expiration, the distributed RAN entity maytransmit, to the wireless device, a control message associated with theradio resource configuration information of the first message and/or thesecond message. The control message may indicate, to the wirelessdevice, an activation of one or more configurations configured based onthe radio resource configuration information of the first message. In anexample, the control message may indicate a cellactivation/deactivation, cell configuration activation, radio resourceconfiguration activation, periodic radio resource configurationactivation (e.g. semi-persistent scheduling resource activation, grantfree resource activation, and/or the like), radio transmission powerconfiguration activation, sidelink communication configurationactivation, and/or the like configuration activation for the distributedRAN entity, the wireless device, and/or the first cell. In an example,the control message may be transmitted via a medium access control (MAC)layer message (e.g. MAC control element), a physical layer message (e.g.physical downlink control channel (PDCCH) order, DCI), and/or the like.

In an example, as shown in FIG. 25, a wireless device may indicate, to agNB-DU, confirmation of RRC configurations.

In an example, the wireless device may transmit an RRC configurationconfirmation indicating that the wireless device complies at least oneof the radio resource configuration information of the third message. Byreceiving the RRC configuration confirmation, the distributed RAN entitymay consider that the wireless device complies at least one ofconfigurations of the radio resource configuration informationassociated with the first message and/or the second message. In anexample, the RRC configuration confirmation may be transmitted via amedium access control (MAC) control element and/or a physical layermessage.

In an example, the first message, the second message, the third message,and/or the RRC configuration confirmation may comprise an RRCconfiguration index. Based on the RRC configuration index, thedistributed RAN entity may recognize that the RRC configurationconfirmation is a confirmation of one or more configurations in theradio resource configuration information associated with the firstmessage and/or the second message.

In an example, if the distributed RAN entity receives the RRCconfiguration confirmation from the wireless device, the distributed RANentity may transmit, to the wireless device, a control messageassociated with the radio resource configuration information of thefirst message and/or the second message. The control message mayindicate, to the wireless device, an activation of one or moreconfigurations configured based on the radio resource configurationinformation of the first message. In an example, the control message mayindicate a cell activation/deactivation, cell configuration activation,radio resource configuration activation, periodic radio resourceconfiguration activation (e.g. semi-persistent scheduling resourceactivation, grant free resource activation, and/or the like), radiotransmission power configuration activation, sidelink communicationconfiguration activation, and/or the like configuration activation forthe distributed RAN entity, the wireless device, and/or the first cell.In an example, the control message may be transmitted via a mediumaccess control (MAC) layer message (e.g. MAC control element), aphysical layer message (e.g. physical downlink control channel (PDCCH)order, DCI), and/or the like.

Processing delay requirements for RRC procedures: The UE performancerequirements for RRC procedures may be specified in the followingtables, by means of a value N, N=the number of lms subframes from theend of reception of the E-UTRAN->UE message on the UE physical layer upto when the UE may be ready for the reception of uplink grant for theUE->E-UTRAN response message with no access delay other than theTTI-alignment (e.g. excluding delays caused by scheduling, the RAprocedure or physical layer synchronization).

FIG. 26 and/or FIG. 27 shows a table of example UE performancerequirements for RRC procedures for wireless devices (UEs).

In an example, a central RAN entity may transmit, to a distributed RANentity, a first message comprising a radio resource configurationinformation associated with a first cell for a wireless device. Thecentral RAN entity may receive, from the distributed RAN entity, asecond message in response to the first message. The central RAN entitymay transmit, to the wireless device via the distributed RAN entity, athird message at least based on the second message. The third messagemay comprise a radio resource control (RRC) configuration informationassociated with one or more elements of the radio resource configurationinformation. The central RAN entity may receive, from the wirelessdevice via the distributed RAN entity, a fourth message confirming oneor more elements of the RRC configuration information in response to thethird message.

In an example, the distributed RAN entity may decode the fourth message,and/or may transmit, to the wireless device, a control messageassociated with the radio resource configuration information in responseto the fourth message. In an example, the fourth message may betransmitted to the wireless device via the distributed RAN entity. An F1message may convey the fourth message from the central RAN entity to thedistributed RAN entity. The F1 message may comprise the fourth messageand an indication indicating that the distributed RAN entity needs todecode the fourth message. The distributed RAN entity may decode thefourth message based on the indication.

In an example, the distributed RAN entity may receive, from the centralradio access network entity, a fifth message indicating that the centralradio access network entity transmitted the radio resource controlconfiguration information to the wireless device and/or receivedresponse message. The distributed RAN entity may transmit, to thewireless device, a control message associated with the radio resourceconfiguration information in response to the fifth message.

In an example, the radio resource configuration information maycomprise: a secondary cell addition/modification/release request; aperiodic resource configuration request; a request for configuring oneor more radio resource; configurations of one or more radio resources;and/or the like. The control message may be transmitted via at least oneof: a medium access control (MAC) control element (CE); a physicaldownlink control channel (PDCCH) order; and/or the like. In an example,the control message may comprise a secondary cell activation command, aperiodic resource configuration activation command, and/or the like.

In an example, when a gNB is split into a gNB-CU and a gNB-DU, a gNB-CUmay provide at least an RRC layer and/or a gNB-DU may provide at leastone of a physical layer and/or a MAC layer. In an example, a gNB maydetermine beam configuration parameters based on physical layer statusinformation for wireless devices. In existing technologies, a radioresource control function and a physical layer monitoring andconfiguration function are performed in different base station units(e.g. a gNB-CU and a gNB-DU). Implementation of existing beamconfiguration and/or application mechanisms of a gNB-CU and a gNB-DU mayincrease misaligned parameter configurations for wireless devices. Theexisting technology may decrease radio channel reliability and increasea packet transmission/reception failure rate of wireless devices. Theexisting technology may increase call dropping rate and/or packettransmission delay when a gNB comprises a gNB-CU and a gNB-DU. There isa need to enhance signaling among a gNB-DU, a gNB-CU and a wirelessdevice to configure beams for a wireless device.

Example embodiments enhance beam configuration and/or applicationmechanisms of a gNB-CU and/or gNB-DU when a gNB-DU provides lower layerfunctions of a gNB and a gNB-CU provides upper layer functions. Exampleembodiments may enhance interactions of a gNB-CU and a gNB-DU toconfigure beam configuration parameters and/or apply configured beamparameters for wireless devices and/or cells. Example embodiments mayincrease connection reliability and decrease packettransmission/reception delay of wireless devices by enhancing beamparameter configuration and/or parameter application mechanism of agNB-CU and a gNB-DU for wireless devices and/or cells.

A NR (New Radio) may support both single beam and multi-beam operations.In a multi-beam system, a gNB may need to perform a downlink beamsweeping to provide coverage for DL synchronization signals (SSs) andcommon control channels. To enable UEs to access the cell, the UEs mayneed the similar sweeping for UL direction.

In the single beam scenarios, the network may configure time-repetitionwithin one synchronization signal (SS) block, which may comprise atleast PSS (Primary synchronization signal), SSS (Secondarysynchronization signal), and PBCH (Physical broadcast channel), in awide beam. In multi-beam scenarios, the network may configure at leastsome of these signals and physical channels (e.g. SS Block) in multiplebeams such that a UE identifies at least OFDM symbol index, slot indexin a radio frame and radio frame number from an SS block.

An RRC_INACTIVE or RRC_IDLE UE may need to assume that an SS Block mayform an SS Block Set and, an SS Block Set Burst, having a givenperiodicity. In multi-beam scenarios, the SS Block may be transmitted inmultiple beams, together forming an SS Burst. If multiple SS Bursts areneeded to transmit beams, these SS Bursts together may form an SS BurstSet as illustrated in FIG. 31. FIG. 31 illustrates examples of differentconfigurations of an SS Burst Set. Top: Time-repetition within one SSBurst in a wide beam. Middle: Beam-sweeping of a small number of beamsusing one SS Burst in the SS Burst Set. Bottom: Beam-sweeping of alarger number of beams using more than one SS Burst in the SS Burst Setto form a complete sweep.

In the multi-beam scenario, for the same cell, PSS/SSS/PBCH may berepeated to support cell selection/reselection and initial accessprocedures. There may be some differences in the conveyed PRACHconfiguration implied by the TSS (Tertiary synchronization signal) on abeam basis within an SS Burst. Under the assumption that PBCH carriesthe PRACH configuration, a gNB may broadcast PRACH configurationspossibly per beam where the TSS may be utilized to imply the PRACHconfiguration differences.

FIG. 32 illustrates an example of an RA procedure comprisingbroadcasting multiple SS blocks.

In an example, the base station may transmit to a wireless device one ormore messages comprising configuration parameters of one or more cells.The configuration parameters may comprise parameters of a plurality ofCSI-RS signal format and/or resources. Configuration parameters of aCSI-RS may comprise one or more parameters indicating CSI-RSperiodicity, one or more parameters indicating CSI-RS subcarriers (e.g.resource elements), one or more parameters indicating CSI-RS sequence,and/or other parameters. Some of the parameters may be combined into oneor more parameters. A plurality of CSI-RS signals may be configured. Inan example, the one or more message may indicate the correspondencebetween SS blocks and CSI-RS signals. The one or more messages may beRRC connection setup message, RRC connection resume message, and/or RRCconnection reconfiguration message. In an example, a UE in RRC-Idle modemay not be configured with CSI-RS signals and may receive SS blocks andmay measure a pathloss based on SS signals. A UE in RRC-connected mode,may be configured with CSI-RS signals and may be measure pathloss basedon CSI-RS signals. In an example, a UE in RRC inactive mode may measurethe pathloss based on SS blocks, e.g. when the UE moves to a differentbase station that has a different CSI-RS configuration compared with theanchor base station.

Example PRACH Burst/RACH Resource Partitioning

In a multi-beam system, a NR may configure different types of PRACHresources that may be associated with SS blocks and/or DL beams. In NR,a PRACH transmission occasion may be defined as the time-frequencyresource on which a UE transmits a preamble using the configured PRACHpreamble format with a single particular Tx beam and for which gNBperforms PRACH preamble detection. One PRACH occasion may be used tocover the beam non-correspondence case. gNB may perform RX sweep duringPRACH occasion as UE TX beam alignment is fixed during single occasion.A PRACH burst may mean a set of PRACH occasions allocated consecutivelyin time domain, and a PRACH burst set may mean a set of PRACH bursts toenable full RX sweep. FIG. 33 illustrates an example of configured PRACHoccasion, PRACH burst, and PRACH burst set. FIG. 33 illustrates anexample of a RACH Occasion, RACH Burst and RACH Burst Set.

There may be an association between SS blocks (DL signal/channel) andPRACH occasion and a subset of PRACH preamble resources. One PRACHoccasion may comprise a set of preambles. In multi beam operation, thegNB may need to know which beam or set of beams it may use to send RARand the preambles may be used to indicate that. NR may configurefollowing partitioning and mappings in multi beam operation:

The timing from SS block to the PRACH resource may be indicated in theMIB. In an example, different TSS may be used for different timings suchthat the detected sequence within TSS indicates the PRACH resource. ThisPRACH configuration may be specified as a timing relative to the SSblock, and may be given as a combination of the payload in the MIB andanother broadcasted system information.

Association between SS block and a subset of RACH resources and/or asubset of preamble indices may be configured so that TRP may identifythe best DL beam for a UE according to resource location or preambleindex of received preamble. An association may be independent and atleast either a subset of RACH resources or subset of preamble indicesmay not be allowed to be associated with multiple SS blocks.

Example SS-Block Specific PRACH Preamble Resources

PRACH resources may be partitioned on SS-blocks basis in multiple beamsoperation. There may be one to one and/or many to one mapping betweenSS-blocks and PRACH occasions. FIG. 34 illustrates an example of TDD(FIG. 34(a))/FDD (FIG. 34(b)) based one to one mapping and multi-to-onemapping (FIG. 34(c)) between SS-blocks and PRACH occasions.

UE may detect SS-block based on DL synchronization signals anddifferentiate SS-blocks based on the time index. With one-to-one mappingof beam or beams used to transmit SS-block and a specific PRACHoccasion, the transmission of PRACH preamble resource may be anindication informed by a UE to gNB of the preferred SS-block. This waythe PRACH preamble resources of single PRACH occasion may correspond tospecific SS-block and mapping may be done based on the SS-block index.There may be one to one mapping between an SS-block beam and a PRACHoccasion. There may not be such mapping for the SS-block periodicity andRACH occasion periodicity.

Depending on the gNB capability (e.g. the used beamformingarchitecture), there may not be one to one mapping between singleSS-block and single RACH occasion. In case beam or beams used fortransmitting SS-block and receiving during RACH occasion do notcorrespond directly, e.g., gNB may form receive beams that covermultiple SS-blocks beams, the preambles of PRACH occasion may be dividedbetween the different SS-blocks in a manner that a subset of PRACHpreambles map to specific SS-block. FIG. 34 illustrates an example ofTDM and FDM mapping of PRACH resources.

Example Beam-Specific PRACH Resources

With beam-specific PRACH resources, a gNB DL TX beam may be associatedwith a subset of preambles. The beam specific PRACH preambles resourcesmay be associated with DL TX beams that are identified by periodicalbeam and cell specific CSI-RS for L3 Mobility (same signals may be usedfor L2 beam management/intra-cell mobility as well). A UE may detect thebeams without RRC configuration, e.g., reading the beam configurationfrom minimum SI (MIB/SIB).

The PRACH resource mapping to specific beams may use SS-blockassociation. Specific beams may be associated with the beams used fortransmitting SS-block as illustrated in FIG. 35. In FIG. 35, gNB maytransmit SS-block using one or multiple beams (in case ofanalogue/hybrid beamforming), but individual beams may not be detected.From the UE perspective, this is a single beam transmission. In FIG. 35,gNB may transmit CSI-RS (for Mobility) using individual beams associatedwith specific SS-block. A UE may detect individual beams based on theCSI-RS.

FIG. 35 illustrates an example of one or more beams configured with anSS block and FIG. 35 illustrates an example of one or more beamsconfigured with CSI-RS.

PRACH occasion may be mapped to corresponding SS-block, and a set ofPRACH preambles may be divided between beams as illustrated in FIG. 36.Similar to mapping of multiple SS-blocks to single PRACH occasion,multiple beams of an SS-block may be mapped to at least one PRACHoccasion as illustrated in FIG. 36.

FIG. 36 illustrates an example of mapping beam specific preambles toPRACH occasion with one-to-one mapping and FIG. 36 illustrates anexample of mapping beam specific preambles to PRACH occasion withk-to-one mapping.

If a PRACH occasion is configured with k preambles, and a PRACH occasionis configured to be SS-block specific, the whole set of preambles may beused to indicate the specific SS-block. In this case, there may be NPRACH occasions corresponding to N SS-blocks.

If multiple SS-blocks are mapped to single PRACH occasion, then thepreambles may be divided between SS-blocks and depending on the numberof SS-blocks, the available preambles per SS-block may be K/N (Kpreambles, N SS-blocks).

If K SS-block specific preambles are divided between CSI-RS beams in thecorresponding PRACH occasions, the number of available preambles perbeam may be determined by the K preambles/number of beams.

If the preambles are partitioned in SS-block specific manner, the UE mayindicate preferred SS-block but not the preferred individual DL TX beamto gNB.

The network may configure mapping/partitioning PRACH preamble resourcesto SS-blocks and/or to individual beams. A UE may determine the usedpartitioning of PRACH preambles, as much as possible, e.g. based on thePRACH configuration.

Beam-specific PRACH configurations may be configurable when a gNB usesanalog RX beamforming. In that case, when a UE sends, for example, apreamble in a beam-specific time/frequency slot associated with one ormultiple SS Block transmissions, then the gNB may use the appropriate RXbeamforming when receiving the preamble in that time/frequency slot anduse the corresponding DL beam when transmitting the RAR. Hence,beam-specific PRACH configurations may allow the gNB to direct its Rxbeamforming in the direction of the same beam when monitoring theassociated PRACH resources.

Example Subsequent Transmissions

In the multi-beam RACH scenario, thanks to the mapping between DL SSbeams and PRACH configuration, e.g. time/frequency slot and possiblypreamble partitioning, a UE may be under the coverage of a given DL beamor at least a subset of them in a cell. That may enable the network tosend a RAR in this best DL beam and/or perform a more optimized beamsweeping procedure e.g. not transmitting the same RAR message inpossible beams (e.g. transmitting the RAR in a single beam as in thefigure below) as illustrated in FIG. 37.

FIG. 37 illustrates an example of an RA procedure with multi-beam; a UEdetects the second SS blocks and thereby transmits a preamble on a RACHresource corresponding to the second SS block to inform gNB of thepreferred beam. gNB responds with a RAR using the beam that the UEprefers.

Example Contention-Free RACH with Multi-Beam Operations

NR may support the contention-free scenarios in a way to provide adedicated RACH resource for the preamble transmission as in LTE forhandover, DL data arrival, positioning and obtaining timing advancealignment for a secondary TAG. For the handover case, a UE may beconfigured to measure on one or more SS blocks or other RS in aneighboring cell. If one of the neighboring cell SS-block measurementstriggers a handover request, the source gNB may signal a preferred beamindex in a handover request to the target gNB. The target gNB in turnmay provide a beam-specific dedicated RACH resource (including preamble)in the handover command. In an example, the target gNB may provide a setof dedicated resources e.g. one for at least one SS-block in thehandover command. The UE then may transmit Msg1 using the dedicatedpreamble corresponding to the preferred DL beam in the target cell.

In an example, a cell may be operated with one or more beams employing amulti-antenna system. A beam may have a spatial direction, and/or maycover a part of a cell coverage area. A combination of one or more beamspatial areas may form a cell coverage. In an example, a beamtransmitting a synchronization signal and/or receiving a signal from awireless device may be swept over a cell coverage area in apredetermined way. A synchronization signal index, a synchronizationsignal scheduling information, and/or a synchronization signal sequenceinformation may be used to identify a swept beam. A swept beam maybroadcast one or more control information comprising at least one of asystem information, a master information, a PDCCH, a PRACH resource, arandom access preamble information, a synchronization signal, areference signal, and/or the like. In an example, a beam may transmit areference signal (e.g. CSI-RS). A beam may be also identified by areference signal (e.g. CSI-RS, DM-RS, and the like) index, a referencesignal scheduling information, and/or a reference signal sequenceinformation.

In an example, one or more beams may be managed via a set of L1/L2procedures to acquire and maintain a set of TRP(s)(TransmissionReception Point) and/or UE beams that may be used for DL and ULtransmission/reception, which may include at least following aspects:Beam determination (for TRP(s) or UE to select of its own Tx/Rxbeam(s)), Beam measurement (for TRP(s) or UE to measure characteristicsof received beamformed signals), Beam reporting (for UE to reportinformation of beamformed signal(s) based on beam measurement), and/orBeam sweeping (operation of covering a spatial area, with beamstransmitted and/or received during a time interval in a predeterminedway).

In an example, the followings may be defined as Tx/Rx beamcorrespondence at TRP and UE. Tx/Rx beam correspondence at TRP holds ifat least one of the following is satisfied: TRP may be able to determinea TRP Rx beam for the uplink reception based on UE's downlinkmeasurement on TRP's one or more Tx beams; and/or TRP may be able todetermine a TRP Tx beam for the downlink transmission based on TRP'suplink measurement on TRP's one or more Rx beams. Tx/Rx beamcorrespondence at UE may hold if at least one of the following issatisfied: UE may be able to determine a UE Tx beam for the uplinktransmission based on UE's downlink measurement on UE's one or more Rxbeams; UE may be able to determine a UE Rx beam for the downlinkreception based on TRP's indication based on uplink measurement on UE'sone or more Tx beams; and/or capability indication of UE beamcorrespondence related information to TRP may be supported.

In an example, the following DL L1/L2 beam management procedures (e.g.P-1, P-2, and P-3) may be supported within one or multiple TRPs. P-1 maybe used to enable UE measurement on different TRP Tx beams to supportselection of TRP Tx beams/UE Rx beam(s). For beamforming at TRP, ittypically may include a intra/inter-TRP Tx beam sweep from a set ofdifferent beams. For beamforming at UE, it may include a UE Rx beamsweep from a set of different beams. P-2 may be used to enable UEmeasurement on different TRP Tx beams to possibly change inter/intra-TRPTx beam(s). From a possibly smaller set of beams for beam refinementthan in P-1. P-2 may be a special case of P-1. P-3 may be used to enableUE measurement on the same TRP Tx beam to change UE Rx beam in the caseUE uses beamforming. At least network triggered aperiodic beam reportingmay be supported under P-1, P-2, and P-3 related operations.

In an example, UE measurement based on RS for beam management (at leastCSI-RS) may be composed of K (=total number of configured beams) beams,and/or UE may report measurement results of N selected Tx beams, where Nmay not be necessarily fixed number. The procedure based on RS formobility purpose may be not precluded. Reporting information may atleast include measurement quantities for N beam (s) and informationindicating N DL Tx beam(s), if N<K. Specifically, when a UE isconfigured with K′>1 non-zero power (NZP) CSI-RS resources, a UE mayreport N′ CRIs (CSI-RS Resource Indicator). A UE may be configured withthe following high layer parameters for beam management. N≥1 reportingsettings, M≥1 resource settings: the links between reporting settingsand resource settings may be configured in the agreed CSI measurementsetting; CSI-RS based P-1 & P-2 may be supported with resource andreporting settings; and/or P-3 may be supported with or withoutreporting setting. A reporting setting at least including: informationindicating selected beam(s); L1 measurement reporting; time-domainbehavior, e.g. aperiodic, periodic, semi-persistent; and/orfrequency-granularity if multiple frequency granularities are supported.A resource setting at least including: time-domain behavior, e.g.aperiodic, periodic, semi-persistent; RS type, e.g. NZP CSI-RS at least;at least one CSI-RS resource set, with each CSI-RS resource set havingK≥1 CSI-RS resources (Some parameters of K CSI-RS resources may be thesame, e.g. port number, time-domain behavior, density and periodicity ifany).

In an example, a beam reporting may be supported at least based on analternative 1 as follow. UE may report information about TRP Tx Beam(s)that may be received using selected UE Rx beam set(s) where a Rx beamset may refer to a set of UE Rx beams that may be used for receiving aDL signal. It may be UE implementation issues on how to construct the Rxbeam set. One example may be that each of Rx beam in a UE Rx beam setmay correspond to a selected Rx beam in each panel. For UEs with morethan one UE Rx beam sets, the UE may report TRP Tx Beam(s) and anidentifier of the associated UE Rx beam set per reported TX beam(s).Different TRP Tx beams reported for the same Rx beam set may be receivedsimultaneously at the UE. Different TRP TX beams reported for differentUE Rx beam set may not be possible to be received simultaneously at theUE.

In an example, a beam reporting may be supported at least based on analternative 2 as follow. UE may report information about TRP Tx Beam(s)per UE antenna group basis where UE antenna group may refer to receiveUE antenna panel or subarray. For UEs with more than one UE antennagroup, the UE may report TRP Tx Beam(s) and an identifier of theassociated UE antenna group per reported TX beam. Different TX beamsreported for different antenna groups may be received simultaneously atthe UE. Different TX beams reported for the same UE antenna group maynot be possible to be received simultaneously at the UE.

In an example, NR may support the following beam reporting considering Lgroups where L>=1 and/or each group may refer to a Rx beam set(alternative 1) or a UE antenna group (alternative 2) depending on whichalternative may be adopted. For each group L, UE may report at least thefollowing information: information indicating group at least for somecases; measurement quantities for N_L beam(s), which may support L1 RSRPand CSI report (when CSI-RS is for CSI acquisition); and/or informationindicating N_L DL Tx beam(s) when applicable. This group based beamreporting may be configurable per UE basis. This group based beamreporting may be turned off per UE basis, e.g. when L=1 or N_L=1. Groupidentifier may not be reported when it is turned off.

In an example, NR (New Radio) may support that UE may be able to triggermechanism to recover from beam failure. Beam failure event may occurwhen the quality of beam pair link(s) of an associated control channelfalls low enough (e.g. comparison with a threshold, time-out of anassociated timer). Mechanism to recover from beam failure may betriggered when beam failure occurs. The beam pair link may be used forconvenience, and may or may not be used in specification. Network mayconfigure to UE with resources for UL transmission of signals forrecovery purpose. Configurations of resources may be supported where thebase station may be listening from all or partial directions, e.g.random access region. The UL transmission/resources to report beamfailure may be located in the same time instance as PRACH (resourcesorthogonal to PRACH resources) and/or at a time instance (configurablefor a UE) different from PRACH. Transmission of DL signal may besupported for allowing the UE to monitor the beams for identifying newpotential beams.

In an example, NR may support beam management with and withoutbeam-related indication. When beam-related indication is provided,information pertaining to UE-side beamforming/receiving procedure usedfor CSI-RS-based measurement may be indicated through QCL (QuasiCo-Location) to UE. NR may support using the same or different beams oncontrol channel and the corresponding data channel transmissions.

In an example, for NR-PDCCH transmission supporting robustness againstbeam pair link blocking, UE may be configured to monitor NR-PDCCH on Mbeam pair links simultaneously, where M≥1 and the maximum value of M maydepend at least on UE capability. UE may be configured to monitorNR-PDCCH on different beam pair link(s) in different NR-PDCCH OFDMsymbols. Parameters related to UE Rx beam setting for monitoringNR-PDCCH on multiple beam pair links may be configured by higher layersignaling or MAC CE and/or considered in the search space design. Atleast, NR may support indication of spatial QCL assumption between an DLRS antenna port(s), and DL RS antenna port(s) for demodulation of DLcontrol channel. Candidate signaling methods for beam indication for aNR-PDCCH (i.e. configuration method to monitor NR-PDCCH) may be MAC CEsignaling, RRC signaling, DCI signaling, specification-transparentand/or implicit method, and combination of these signaling methods.Indication may not be needed for some cases.

In an example, for reception of unicast DL data channel, NR may supportindication of spatial QCL assumption between DL RS antenna port(s) andDMRS antenna port(s) of DL data channel. Information indicating the RSantenna port(s) may be indicated via DCI (downlink grants). Theinformation may indicate the RS antenna port(s) which may be QCL-ed withDMRS antenna port(s). Different set of DMRS antenna port(s) for the DLdata channel may be indicated as QCL with different set of RS antennaport(s). Indication may not be needed for some cases.

In an example, a CU-DU interface between CU and DU may be defined as anF1 interface. In an example, there may be transport networks withperformances that may vary from high transport latency to low transportlatency in the real deployment. For transport network with highertransport latency, higher layer splits may be applicable. For transportnetwork with lower transport latency, lower layer splits may also beapplicable and preferable to realize enhanced performance (e.g.centralized scheduling). Thus, preferable option may be differentbetween different types of transport networks (ranging from lower layersplit for transport networks with lower transport latency to higherlayer split for transport networks with higher transport latency).Furthermore, within lower layer split discussion, there may be bothdemands to reduce transport bandwidth and demands to support efficientscheduling and advanced receivers.

In an example, LTE<->NR interworking may be based onDual-Connectivity-like mechanisms. Such approach may not imply aparticular functional split. The requirement that may be extrapolated bythe LTE-NR tight interworking requirement may be that of allowingaggregation of PDCP functionalities, in case of split bearers.

In an example, some possible options for the granularity of the CU/DUfunctional split may be per CU (each CU may a fixed split, and DUs maybe configured to match this) and/or per DU (each DU may be configuredwith a different split. The choice of a DU split may depend on specifictopology or backhaul support in an area). For 2 cases, one possible wayon how the CU/DU decide or coordinate the split may be throughconfiguration. Alternatively, the split may be negotiated taking intoaccount capabilities of the two units (CU and DU), and deploymentpreference e.g. based on backhaul topology. In an example, additionalsplit granularity options may be as followings: per UE (different UEsmay have different service levels, or belong to different categories,that may be best served in different ways by the RAN e.g. a low rateIoT-type UE with no need for low latency may not necessarily requirehigher layer functions close to the RF), per bearer (different bearersmay have different QOS requirements that may be best supported bydifferent functionality mapping. For example, QCI=1 type bearer mayrequire low delay but may not SDU error sensitive, while eMBB may not bedelay sensitive but may have challenging requirements on throughput andSDU error rate), and/or per slice (it may be expected that each slicemay have at least some distinctive QOS requirements. Regardless of howexactly a slice is implemented within the RAN, different functionalitymapping may be suitable for each slice).

Per CU and Per DU options may pertain to flexibility of networktopology, and may be straightforward to support. Whether procedures maybe required to handle the initial configuration (or O&M may be reliedupon) may not be discussed during the study phase. Note that in the PerDU option, one CU may need to support different split levels indifferent interfaces, which may not the case in the Per CU option.Further granularity (Per UE, Per bearer, Per slice) may require analysisand justification based on QoS and latency requirements. Note that thePer UE, Per bearer and Per slice options may imply that a particularinstance of the interface between CU/DU may need to supportsimultaneously multiple granularity levels on user plane. The baselinemay be CU based or DU based. If there are demands to have finergranularity (e.g. Per UE,Per bearer, Per slice), justification may bemade clear first.

In an example, dynamicity may imply that the protocol distribution andthe interface between the CU and DU may need to be reconfigured. If theswitching occurs in CU-DU setup procedure (F1 interface setupprocedure), the interface design may not be influenced largely as thesplit option may not be changed during operation. If the switchingoccurs during operation, there may be impact on complexity of interface.

In an example, it may be possible that not all of the defined functionalsplits allow for having RRM functions like Call Admission Control andLoad balancing in the CU controlling multiple DUs. This may allow forthe potential of increased efficiency in inter-cell coordination for RRMfunctions like the coordination of interference management, loadbalancing and Call Admission Control. However, that efficiency may onlybe realized if the CU may have reliable and accurate understanding ofthe current environment at the DU which may include issues beyond justradio conditions, but may include current processing capabilities, or inthe case of wireless or mesh backhauling help in determining currentterrestrial capacity.

In an example, functional split Option 5, Option 6, Option 7 and Option8 may allow for scheduling of data transmission in the CU. Havingcentralized scheduling may provide benefit particularly for interferencemanagement and coordinated transmission in multiple cells (like softhandover in UMTS, or CoMP in LTE). However, this may require the CU tohave an even better understanding of the state of the DU radioconditions than for CAC and other centralized RRM functions. It also mayrequire either very low latency/jitter transport or sufficiently tightcoordination of timing and reception of user plane data (one solutionmay be the window mechanism used on the UP in UMTS), but this may bechallenging particularly for lower latency use cases in NR.Centralization of RAN functions may have strong potential for somebenefits such as reduced cost, improved scalability, more efficientinter-cell coordination for interference management as well as improvedmobility in ultra-dense deployments.

In an example, the RRC related functions may be located in the CU. TheRRC message between the gNB and the UE may be transferred through theinterface (e.g. F1 interface) between the CU and the DU. RRC messagesmay require a differentiated transport between CU and DU compared todata transport, e.g. in terms of robustness and delay.

In an example, F1-C and F1-U may provide C-plane and U-plane over F1interface, respectively. In this architecture, CU and DU may be definedas follows. Central Unit (CU) may be a logical node that may include asubset of the gNB functions as listed excepting those functionsallocated exclusively to the DU. CU may control the operation of DUs.Distributed Unit (DU) may be a logical node that may include, dependingon the functional split option, a subset of the gNB functions. Theoperation of DU may be controlled by the CU.

In an example, gNB-CU UE F1AP ID may be allocated so as to uniquelyidentify the UE over the F1 interface within a gNB-CU and an associatedgNB-DU. When a gNB-DU receives a gNB-CU UE F1AP ID, it may store it forthe duration of the UE-associated logical F1-connection for this UE. ThegNB-CU UE F1AP ID may be unique within the gNB-CU logical node and theassociated gNB-DU logical node. The definition of the AP ID may bepending the decision on whether the DU is connected to multiple CU.UE-associated signaling may be one or more F1AP messages associated toone UE, wherein the one or more FlAP messages may use the UE-associatedlogical F1-connection for association of the message to the UE in gNB-DUand gNB-CU. The UE-associated logical F1-connection may use theidentities gNB-CU UE F1AP ID. For a received UE associated FLAP message,the gNB-CU and gNB-DU may identify the associated UE based on the gNB-CUUE FlAP ID IE. The UE-associated logical F1-connection may exist beforethe F1 UE context is setup in gNB-DU.

In an example, the purpose of the F1 Setup procedure may be to exchangeapplication level data needed for the gNB-DU and the gNB-CU to correctlyinteroperate on the F1 interface (i.e. CU-DU interface). This proceduremay be the first FLAP procedure triggered after the TNL association mayhave become operational. The procedure may use non-UE associatedsignaling. This procedure may erase existing application levelconfiguration data in the two nodes and may replace it by the onereceived and may clear gNB-CU overload state information at the gNB-DU.If the gNB-DU and gNB-CU do not agree on retaining the UE Contexts, thisprocedure may re-initialize the F1AP UE-related contexts and may eraserelated signaling connections in the two nodes like a Reset procedurewould do.

In an example, as shown in FIG. 28, FIG. 29 and/or FIG. 30, a gNB-CU(e.g. CU, central unit) may configure beam configuration parameters.

In an example embodiment, a central radio access network (RAN) entity(Central Unit, CU, gNB-CU) may transmit a beam management message to adistributed RAN entity (Distributed Unit, DU, gNB-DU) via an F1interface (i.e. an interface between CU and DU). The beam managementmessage may be configured to activate one or more beams, to deactivateone or more beams, and/or to modify one or more beam configurationparameters for one or more beams. In an example, the beam managementmessage may be transmitted at least based on radio resource statusand/or interference information received from one or more DUs, one ormore neighbor base stations, and/or one or more wireless devices. The DUreceiving the beam management message may activate/deactivate one ormore beams and/or modify one or more beam configuration parameters forone or more beams at least based on the beam management message.

In an example, a first DU may receive, from a CU, a first messagecomprising one or more beam configuration parameters. The first messagemay be transmitted via an F1 interface between the first DU and the CU.The first message may be configured to request the DU at least one of:to activate (e.g. configure) a first beam; to deactivate (e.g. release)a second beam; and/or to modify one or more beam configurationparameters for a third beam. The first beam, the second beam, and/or thethird beam may be to serve a first cell. In an example, a type of thefirst beam, the second beam, and/or the third beam may be asynchronization signal (SS) beam, a cell specific channel stateinformation reference signal (CSI-RS) beam, a UE specific CSI-RS beam,and/or the like. The first message may further comprise a cellidentifier of the first cell. The cell identifier may be a global cellidentifier, a physical cell identifier, a cell identifier at leastunique at the first DU, and/or the like.

In an example, the one or more beam configuration parameters maycomprise at least one of: a beam index, a beam scheduling information, asynchronization signal configuration information (e.g. SS blockscheduling information), a reference signal configuration information(e.g. CSI-RS and/or DM-RS scheduling information), a beam identifier,and/or the like. In an example, one or more elements of the firstmessage may be determined at least based on information received from atleast one of a first wireless device, a neighboring base station, and/ora second distributed radio access network entity.

In an example, if the first message is to request the first DU toactivate (e.g. configure) a first beam, the first message may comprisean activation indication (e.g. configuration indication) indicating arequest (e.g. a configuration parameter) to activate (e.g. configure)the first beam. In an example, the activation indication (e.g. theconfiguration indication) may be based on one or more first measurementreports from one or more wireless device. The one or more firstmeasurement reports may indicate that a coverage area of the first celland/or neighboring cells of the first cell is overloaded (congested),and/or that wireless devices in the coverage area are experiencing lowradio channel qualities. By increasing the number of activated beams(e.g. configured beams), the first cell may resolve the congestionsituation, may compensate coverage holes in the area of the first cell,and/or may increase a channel quality of a wireless device served viathe first cell.

In an example, if the first message is to request the first DU todeactivate (e.g. release) a second beam, the first message may comprisea deactivation indication (e.g. release indication) indicating a request(e.g. release configuration parameter) to deactivate (e.g. release) thesecond beam. In an example, the deactivation indication (e.g. releaseindication) may be based on one or more second measurement reports fromone or more wireless device. The one or more second measurement reportsmay indicate that a coverage area of the second cell and/or neighboringcells of the second cell has low traffic, and/or that wireless devicesin the coverage area are experiencing high radio channel qualities (e.g.high enough to decrease the number of beams). By decreasing the numberof activated beams (e.g. configured beams), the second cell may reduceoperation complexity, may reduce interference towards neighboring cellsof the second cell, and/or may increase radio resource usage (e.g.because the second cell may reduce the number of sweeping beams).

In an example, if the first message is to modify one or more beamconfiguration parameters for a third beam, the first message maycomprise a modification indication indicating a request to modify one ormore beam configuration parameters of the third beam. In an example, themodification indication may be based on one or more third measurementreports from one or more wireless device. The one or more thirdmeasurement reports may indicate that a coverage area of the third celland/or neighboring cells of the third cell is overloaded (congested)and/or has low traffic, and/or that wireless devices in the coveragearea are experiencing low or high radio channel qualities. By modifyingthe one or more beam configuration parameters for the third cell, thethird cell may control service qualities for wireless devices and/orsystem performance. In an example, the one or more beam configurationparameters may comprise beam steering direction, transmission power,beam sweeping scheduling (e.g. periodicity, sweeping timing, beamserving duration of the third beam compared to other beams of the thirdcell, the number of beam activations of the third beam in a sweepingperiod). For example, by increasing the beam serving duration of thethird beam and/or the number of beam activations of the third beam,traffic capacity of the area of the third beam may increase.

In an example, the one or more beam configuration parameters maycomprise a random access (RA) configurations associated with the firstbeam, the second beam, and/or the third beam (e.g. RA preamble indexesto be used, RA resource configuration information, and/or the like).

In an example, the CU may determine one or more elements of the firstmessage at least based on a third message that the CU received from atleast one of a first wireless device, a neighboring base station, asecond DU (e.g. the second DU may be the first DU), a core networkentity, and/or an operation and management (OAM). The third message maycomprise a resource status information (e.g. radio resource status,hardware overhead information, and/or the like) of one or more beams ofone or more cells; a resource status information of one or more cells; aload status information of one or more beams of one or more cells (e.g.a number of serving wireless devices, a number of radio resource controlinactive state wireless devices, a random access resource utilizationinformation, and/or the like); a load status information of one or morecells; an uplink receiving interference information of one or morebeams; an uplink receiving interference information of one or morecells; a downlink receiving interference information of one or morebeams; a downlink receiving interference information of one or morecells; a uplink/downlink received signal quality (e.g. received signalpower and/or interference); and/or the like.

In an example, the first DU may transmit, to the CU, a second message inresponse to the first message. The second message may be transmitted viathe F1 interface. The second message may be configured to indicate anacknowledge of one or more elements of the one or more beamconfiguration parameters of the first message. In an example, the secondmessage may further comprise at least one of: an acceptance indicationindicating that the first DU activates the first beam of the first cell,a rejection indication indicating that the first DU does not activatethe first beam, an acceptance indication indicating that the first DUdeactivates the second beam of the first cell, a rejection indicationindicating that the first DU does not deactivate the second beam, anacceptance indication indicating that the first DU modifies at least oneconfiguration parameter of the one or more beam configuration parametersfor the third beam of the first cell, a rejection indication indicatingthat the first DU does not modify the one or more beam configurationparameters for the third beam, and/or the like.

In an example, the first DU may configure beams of the first cell atleast based on the one or more beam configuration parameters of thefirst message. The first DU may activate (e.g. configure) the first beamfor the first cell, may deactivate (e.g. release) the second beam forthe first cell, may modify at least one configuration parameter of theone or more beam configuration parameters of the third beam for thefirst cell, and/or may configure the like. The second message may bedetermined at least based on the configurations of the first DU inresponse to receiving the first message. In an example, the first DU maytransmit, to a plurality of wireless devices via radio interface (e.g.system information, one or more system information blocks, systeminformation block type 1, master information, master information block,UE dedicated message, UE dedicated RRC message, and/or the like), beaminformation updated at least based on the configurations of the first DUin response to receiving the first message. The beam information maycomprise configuration parameters of the first beam activated (e.g.configured) in response to the first message, the third beam modified inresponse to the first message, and/or the like. The configurationparameters may comprise SS block information (e.g. scheduling, timing,resource block, periodicity, frequency, and/or the like information),CSI-RS block information (e.g. scheduling, timing, resource block,periodicity, frequency, and/or the like information). In an example, thefirst DU may transmit the one or more system information blocks (e.g.the system information block type 1, the system information, the masterinformation block) via the CU to wireless devices.

In an example, the CU may transmit, to a wireless device, a fourthmessage based on the second message and/or the first message. The fourthmessage may be a radio resource control (RRC) message. One or moreelements of the fourth message may be determined based on one or moreelements of the first message and/or the second message. The fourthmessage may comprise a cell configuration information of the first cell.The fourth message may comprise RA configuration parameters for one ormore beams of the first cells. The fourth message may comprise one ormore beam configuration parameters of the first cell. The fourth messagemay comprise one or more beam list to be measured, to be accessed, to bemonitored, to be employed, and/or to be stored as a candidate for use bythe wireless device.

In an example, as shown in FIG. 28, FIG. 29 and/or FIG. 30, a gNB-DU(e.g. DU, distributed unit) may configure beam configuration parameters.

In an example, a DU may manage beam configurations (e.g. beam activation(e.g. configuration), beam deactivation (e.g. release), and/or beamconfiguration modification) and/or transmit the beam configurationinformation to a CU. The CU may transmit, to a wireless device, one ormore radio configuration parameters (e.g. system information block, RRCmessage, and/or the like) determined at least based on one or moreelements of the beam configuration information. In an example, the beamconfigurations managed by the DU may be determined at least based onradio resource status information and/or interference information ofneighboring DUs and/or neighboring base stations provided by the CU.

In an example, a first DU may transmit, to a CU, a cell configurationmessage (e.g. system information block, RRC message) comprising one ormore beam configuration parameters. The cell configuration message maybe transmitted via an F1 interface between the first DU and the CU. Thecell configuration message may be configured to inform the CU at leastone of: activation (e.g. configuration) of a first beam; deactivation(e.g. release) of a second beam; and/or modification of one or more beamconfiguration parameters for a third beam. The first beam, the secondbeam, and/or the third beam may be to serve a first cell. In an example,a type of the first beam, the second beam, and/or the third beam may bea synchronization signal (SS) beam, a cell specific channel stateinformation reference signal (CSI-RS) beam, a UE specific CSI-RS beam,and/or the like. The cell configuration message may further comprise acell identifier of the first cell. The cell identifier may be a globalcell identifier, a physical cell identifier, a cell identifier at leastunique at the first DU, and/or the like.

In an example, the one or more beam configuration parameters maycomprise at least one of: a beam index, a beam scheduling information, asynchronization signal configuration information (e.g. SS blockscheduling information), a reference signal configuration information(e.g. CSI-RS and/or DM-RS scheduling information), a beam identifier,and/or the like. In an example, one or more elements of the cellconfiguration message may be determined at least based on informationreceived from at least one of a first wireless device, a neighboringbase station, and/or a second distributed radio access network entity.In an example, one or more elements of the cell configuration messagemay be determined at least based on beam configuration updatesassociated with one or more beams of the first cell. The one or morebeams may be activated, deactivated, and/or modified by the first DU.

In an example, if the cell configuration message is to inform that thefirst DU activates (e.g. configures) a first beam, the cellconfiguration message may comprise an activation indication indicatingan activation of the first beam. In an example, the activation (e.g.configuration) may be based on one or more first measurement reportsfrom one or more wireless device and/or from the CU. The one or morefirst measurement reports may indicate that a coverage area of the firstcell and/or neighboring cells of the first cell is overloaded(congested), and/or that wireless devices in the coverage area areexperiencing low radio channel qualities. By increasing the number ofactivated beams, the first cell may resolve the congestion situation,may compensate coverage holes in the area of the first cell, and/or mayincrease a channel quality of a wireless device served via the firstcell.

In an example, if the cell configuration message is to inform that thefirst DU deactivates (e.g. release) a second beam, the cellconfiguration message may comprise a deactivation (e.g. release)indication indicating a deactivation of the second beam. In an example,the deactivation may be based on one or more second measurement reportsfrom one or more wireless device and/or from the CU. The one or moresecond measurement reports may indicate that a coverage area of thesecond cell and/or neighboring cells of the second cell has low traffic,and/or that wireless devices in the coverage area are experiencing highradio channel qualities (e.g. high enough to decrease the number ofbeams). By decreasing the number of activated beams, the second cell mayreduce operation complexity, may reduce interference towards neighboringcells of the second cell, and/or may increase radio resource usage (e.g.because the second cell may reduce the number of sweeping beams).

In an example, if the cell configuration message is to inform amodification of one or more beam configuration parameters for a thirdbeam, the cell configuration message may comprise a modificationindication indicating a modification of one or more beam configurationparameters of the third beam. In an example, the modification may bebased on one or more third measurement reports from one or more wirelessdevice and/or from the CU. The one or more third measurement reports mayindicate that a coverage area of the third cell and/or neighboring cellsof the third cell is overloaded (congested) and/or has low traffic,and/or that wireless devices in the coverage area are experiencing lowor high radio channel qualities. By modifying the one or more beamconfiguration parameters for the third cell, the third cell may controlservice qualities for wireless devices and/or system performance. In anexample, the one or more beam configuration parameters may comprise beamsteering direction, transmission power, beam sweeping scheduling (e.g.periodicity, sweeping timing, beam serving duration of the third beamcompared to other beams of the third cell, the number of beamactivations of the third beam in a sweeping period). For example, byincreasing the beam serving duration of the third beam and/or the numberof beam activations of the third beam, traffic capacity of the area ofthe third beam may increase.

In an example, the one or more beam configuration parameters maycomprise a random access (RA) configurations associated with the firstbeam, the second beam, and/or the third beam (e.g. RA preamble indexesto be used, RA resource configuration information, and/or the like).

In an example, the first DU may determine beam configurations for thefirst cell and/or one or more elements of the cell configuration messageat least based on a status information message that the first DUreceived from at least one of a first wireless device, the CU, aneighboring base station, and/or an operation and management (OAM). Thestatus information message may comprise a resource status information(e.g. radio resource status, hardware overhead information, and/or thelike) of one or more beams of one or more cells; a resource statusinformation of one or more cells; a load status information of one ormore beams of one or more cells (e.g. a number of serving wirelessdevices, a number of radio resource control inactive state wirelessdevices, a random access resource utilization information, and/or thelike); a load status information of one or more cells; an uplinkreceiving interference information of one or more beams; an uplinkreceiving interference information of one or more cells; a downlinkreceiving interference information of one or more beams; a downlinkreceiving interference information of one or more cells; auplink/downlink received signal quality (e.g. received signal powerand/or interference); and/or the like.

In an example, the CU may transmit, to the first DU, a cellconfiguration response message in response to the cell configurationmessage. The cell configuration response message may be transmitted viathe F1 interface. The cell configuration response message may beconfigured to indicate an acknowledge of one or more elements of the oneor more beam configuration parameters of the cell configuration message.In an example, the cell configuration response message may comprise atleast one of: an acknowledge indication for the activation of the firstbeam, the deactivation of the second beam, the modification of the oneor more beam configuration parameters for the third beam, and/or thelike.

In an example, the first DU may configure the one or more beamconfiguration parameters of the cell configuration message at leastbased on the beam configuration updates of the first cell. The first DUmay activate the first beam for the first cell, may deactivate thesecond beam for the first cell, may modify at least one configurationparameter of the one or more beam configuration parameters of the thirdbeam for the first cell, and/or may configure the like. In an example,the first DU may transmit, to a plurality of wireless devices via radiointerface (e.g. system information, master information, UE dedicatedmessage, and/or the like), beam information updated at least based onthe beam configuration updates of the first DU. The beam information maycomprise configuration parameters of the first beam activated inresponse to the cell configuration message, the third beam modified inresponse to the cell configuration message, and/or the like. Theconfiguration parameters may comprise SS block information (e.g.scheduling, timing, resource block, periodicity, frequency, and/or thelike information), CSI-RS block information (e.g. scheduling, timing,resource block, periodicity, frequency, and/or the like information).

In an example, the CU may transmit, to a wireless device, a radioresource configuration message based on the cell configuration messageand/or the cell configuration response message. The radio resourceconfiguration message may be a radio resource control (RRC) message. Oneor more elements of the radio resource configuration message may bedetermined based on one or more elements of the cell configurationmessage and/or the cell configuration response message. The radioresource configuration message may comprise a cell configurationinformation of the first cell. The radio resource configuration messagemay comprise RA configuration parameters for one or more beams of thefirst cells. The radio resource configuration message may comprise oneor more beam configuration parameters of the first cell. The radioresource configuration message may comprise one or more beam list to bemeasured, to be accessed, to be monitored, to be employed, and/or to bestored as a candidate for use by the wireless device.

In an example, a first distributed RAN entity may receive, from acentral RAN entity, a first message comprising one or more beamconfiguration parameters associated with a serving cell of the firstdistributed RAN entity, wherein the first message may be configured torequest for at least one of: activating a first beam; deactivating asecond beam; and/or modifying configurations of a third beam. The firstdistributed RAN entity may transmit, to the central RAN entity, a secondmessage in response to the first message, wherein the second message maycomprise an indication indicating at least one of: accepting the requestof the first message; and/or rejecting the request of the first message.In an example, the first distributed RAN entity, may configure beamconfigurations at least based on the one or more beam configurationparameters. The first distributed RAN entity may transmit, to aplurality of wireless devices, a beam information that may be determinedat least based on the one or more beam configuration parameters.

In an example, the central radio access network entity may determine oneor more elements of the first message at least based on a third messagereceived from at least one of a first wireless device, a neighboringbase station, and/or a second distributed RAN entity. The third messagemay comprise at least one of: a resource status information of one ormore beams of one or more cells; a resource status information of one ormore cells; a load status information of one or more beams of one ormore cells (e.g. a number of serving wireless devices, a number of radioresource control inactive state wireless devices, a random accessresource utilization information, and/or the like); a load statusinformation of one or more cells; an uplink receiving interferenceinformation of one or more beams; an uplink receiving interferenceinformation of one or more cells; a downlink receiving interferenceinformation of one or more beams; and/or a downlink receivinginterference information of one or more cells.

In an example, the second distributed RAN entity may be the firstdistributed RAN entity. The central RAN entity may transmit, to awireless device, a fourth message comprising one or more radio resourcecontrol configuration parameters at least based on the second message.In an example, the one or more beam configuration parameters maycomprise at least one of: a beam index; a beam scheduling information; abeam transmission power; a beam steering direction; and/or the like.

In an example, a first distributed RAN entity may transmit, to a centralRAN entity, a cell configuration message comprising one or more beamconfiguration parameters, wherein the cell configuration message mayindicate at least one of: an activation of a first beam; a deactivationof a second beam; and/or a configuration modification of a third beam.The first distributed RAN entity may receive, from the central RANentity, a second message acknowledging one or more elements of the cellconfiguration message. The first distributed RAN entity may transmit, toa plurality of wireless devices, a beam information associated with oneor more elements of the one or more beam configuration parameters.

According to various embodiments, a device such as, for example, awireless device, a base station, base station central unit, a basestation distributed unit, a core network entity, and/or the like, maycomprise one or more processors and memory. The memory may storeinstructions that, when executed by the one or more processors, causethe device to perform a series of actions. Embodiments of exampleactions are illustrated in the accompanying figures and specification.Features from various embodiments may be combined to create yet furtherembodiments.

FIG. 38 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. At 3810, a base station central unit maytransmit a first message to a base station distributed unit. The firstmessage may comprise first configuration parameters of a wirelessdevice. At 3820, the base station central unit may receive a secondmessage from the base station distributed unit. The second message mayindicate acknowledgement of the first message. The second message maycomprise second configuration parameters based on the firstconfiguration parameters. At 3830, the base station central unit maytransmit a third message to the wireless device via the base stationdistributed unit. The third message may comprise the secondconfiguration parameters. At 3840, the base station central unit mayreceive a fourth message from the wireless device via the base stationdistributed unit. The fourth message may confirm at least one of thesecond configuration parameters. At 3850, the base station central unitmay transmit a fifth message to the base station distributed unit. Thefifth message may indicate that the wireless device successfullyperformed a reconfiguration procedure based on the second configurationparameters.

According to an embodiment, the second configuration parameters comprisea secondary cell addition indication of a secondary cell. According toan embodiment, the second configuration parameters may comprise asecondary cell modification indication of a secondary cell. According toan embodiment, the second configuration parameters may comprise asecondary cell release indication of a secondary cell. According to anembodiment, the second configuration parameters may comprise periodicresource scheduling information of periodic resources of a cell.According to an embodiment, the second configuration parameters maycomprise a transmission power configuration parameter. According to anembodiment, the second configuration parameters may comprise a sidelinkconfiguration parameter. According to an embodiment, the secondconfiguration parameters may comprise a random access configurationparameter.

According to an embodiment, the second configuration parameters maycomprise a periodic resource scheduling information of periodicresources of a cell. The periodic resource scheduling information maycomprise a periodicity configuration parameter. The periodic resourcescheduling information may comprise a frequency configuration parameter.The periodic resource scheduling information may comprise a numerologyindication parameter.

According to an embodiment, the second configuration parameters maycomprise a random access configuration parameter. The random accessconfiguration parameter may comprise a preamble index. The random accessconfiguration parameter may comprise random access resource information.

According to an embodiment, the base station distributed unit maytransmit to the wireless device and based on the fifth message, a mediumaccess control element may indicate activation of periodic resources.According to an embodiment, the base station distributed unit maytransmit to the wireless device and based on the fifth message, aphysical downlink control channel order may indicate a random accessinitiation command for a secondary cell. According to an embodiment, thebase station distributed unit may transmit to the wireless device andbased on the fifth message, a medium access control control element mayindicate activation or deactivation of a secondary cell.

According to an embodiment, in response to receiving the fifth message,the base station distributed unit based may be configured based on thesecond configuration parameters for the wireless device. According to anembodiment, the second configuration parameters may indicateacknowledgement of at least one of the first configuration parameters.According to an embodiment, the wireless device may reject one or moreof the second configuration parameters. According to an embodiment, thesecond configuration parameters may be for a first cell of the wirelessdevice. According to an embodiment, the second message and the fifthmessage may comprise a radio resource control configuration index mayindicating that the reconfiguration procedure of the fifth message isfor the second configuration parameters. According to an embodiment, thefirst message, the second message, and the fifth message may betransmitted via an F1 interface. According to an embodiment, the thirdmessage and the fourth message may comprise a radio resource controlmessage. According to an embodiment, a base station may comprise thebase station central unit and the base station distributed unit.According to an embodiment, the base station central unit may comprise aradio resource control function for the wireless device.

According to an embodiment, the base station distributed unit maycomprise a medium access control layer function for the wireless device.According to an embodiment, the base station distributed unit maycomprise a physical layer function for the wireless device. According toan embodiment, the base station central unit may transmit to thewireless device, one or more first packets via the base stationdistributed unit. According to an embodiment, the base station centralunit may receive from the wireless device, one or more second packetsvia the base station distributed unit. According to an embodiment, thethird message may comprise a radio resource control reconfigurationmessage. According to an embodiment, the fourth message may comprise aradio resource control reconfiguration complete message.

FIG. 39 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. At 3910, a base station central unit maytransmit first message to a base station distributed unit. The firstmessage may comprise first configuration parameters of a wirelessdevice. At 3920, the base station central unit may receive a secondmessage from the base station distributed unit. The second message mayindicate acknowledgement of the first message. The second message maycomprise second configuration parameters based on the firstconfiguration parameters. At 3930, the base station central unit maytransmit a third message to the wireless device and via the base stationdistributed unit. The third message may comprise the secondconfiguration parameters. At 3940, the base station central unit mayreceive a fourth message from the wireless device and via the basestation distributed unit. The fourth message may report status of areconfiguration procedure of at least one of the second configurationparameters. At 3950, the base station central unit may transmit a fifthmessage to the base station distributed unit. The fifth message mayindicate that the wireless device successfully performed thereconfiguration procedure based on the second configuration parameters.

According to an embodiment, the base station distributed unit maytransmit to the wireless device and based on the fifth message, a mediumaccess control control element. The a medium access control controlelement may indicate activation of periodic resources. The secondconfiguration parameters may comprise periodic resource schedulinginformation of the periodic resources. According to an embodiment, thebase station distributed unit may transmit to the wireless device andbased on the fifth message, a physical downlink control channel order.The a physical downlink control channel order may indicate a randomaccess initiation command for a secondary cell. The second configurationparameters may comprise a secondary cell addition indication of thesecondary cell. The second configuration parameters may comprise asecondary cell modification indication of the secondary cell.

According to an embodiment, the base station distributed unit maytransmit to the wireless device and based on the fifth message, a mediumaccess control control element. The medium access control controlelement may indicate activation or deactivation of a secondary cell. Thesecond configuration parameters may comprise at least one of: asecondary cell addition indication of the secondary cell, or a secondarycell modification indication of the secondary cell.

FIG. 40 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. At 4010, a base station distributed unit mayreceive a first message from a base station central unit. The firstmessage may comprise radio resource configuration parameters of a firstcell for a wireless device. At 4020, the base station distributed unitmay transmit a second message to the base station central unit inresponse to the first message. The second message may indicateacknowledgement of the radio resource configuration parameters. At 4030,the base station distributed unit may forward to the wireless device, athird message received from the base station central unit. The thirdmessage may comprise radio resource control configuration parametersbased on the radio resource configuration parameters. At 4040, the basestation distributed unit may forward to the base station central unit, afourth message received from the wireless device. The fourth message mayconfirm the radio resource control configuration parameters. At 4050,the base station distributed unit may receive a fifth message from thebase station central unit. The fifth message may indicate that thewireless device performed a reconfiguration procedure based on the radioresource configuration parameters. At 4060, the base station distributedunit may configure and in response to receiving the fifth message, thebase station distributed unit based on the radio resource configurationparameters for the wireless device.

FIG. 41 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. At 4110, a base station central unit maytransmit a first message to a base station distributed unit. The firstmessage may comprise first configuration parameters for a wirelessdevice. At 4120, the base station central unit may receive a secondmessage from the base station distributed unit. The second message mayindicate acknowledgement of the first message. The second message maycomprise second configuration parameters determined based on the firstconfiguration parameters. At 4130, the base station central unit maytransmit a third message to the wireless device and via the base stationdistributed unit. The third message may comprise the secondconfiguration parameters. At 4140, the base station distributed unit maystart a configuration timer in response to forwarding the third messageto the wireless device. At 4150, the base station central unit mayreceive a fourth message from the wireless device and via the basestation distributed unit. The fourth message may confirm one or moreelements of the second configuration parameters. At 4160, the basestation distributed unit may consider and in response to expiration ofthe configuration timer, that the wireless device successfully performeda reconfiguration procedure based on the second configurationparameters.

FIG. 42 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. At 4210, a base station central unit maytransmit a first message to a base station distributed unit. The firstmessage may comprise first configuration parameters for a wirelessdevice. At 4220, the base station central unit may receive a secondmessage from the base station distributed unit. The second message mayindicate acknowledgement of the first message. The second message maycomprise second configuration parameters determined based on the firstconfiguration parameters. At 4230, the base station central unit maytransmit to the wireless device and via the base station distributedunit, a third message. The third message may comprise the secondconfiguration parameters. At 4240, the base station central unit mayreceive from the wireless device and via the base station distributedunit, a fourth message. The fourth message may confirm one or moreelements of the second configuration parameters. At 4250, the basestation distributed unit may receive a fifth message from the wirelessdevice. The fifth message may indicate that the wireless devicesuccessfully performed a reconfiguration procedure based on the secondconfiguration parameters. According to an embodiment, the fifth messagemay be transmitted via at least one of: a medium access control layermessage, or a physical layer indication.

FIG. 43 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. At 4310, a base station distributed unit maytransmit a first message to a base station central unit. The firstmessage may comprise one or more beam configuration parameters of afirst cell. The one or more beam configuration parameters may comprise afirst beam index identifying a first beam. The one or more beamconfiguration parameters may comprise first beam scheduling informationof the first beam. At 4320, the base station distributed unit mayreceive a second message from the base station central unit. The secondmessage may indicate acknowledgement of the first message. At 4330, thebase station distributed unit may transmit a system information block toa plurality of wireless devices. The system information block maycomprise the one or more beam configuration parameters of the firstcell. At 4340, the base station distributed unit may transmitsynchronization signals to the plurality of wireless devices via thefirst beam.

According to an embodiment, the first beam scheduling information maycomprise a synchronization signal periodicity, According to anembodiment, the first beam scheduling information may comprise asynchronization signal frequency. According to an embodiment, the firstbeam scheduling information may comprise a channel stateinformation-reference signal periodicity. According to an embodiment,the first beam scheduling information may comprise a channel stateinformation-reference signal frequency. According to an embodiment, thebase station distributed unit may transmit to the plurality of wirelessdevices, the system information block is via the base station centralunit. According to an embodiment, the base station central unit maytransmit to a wireless device, a radio resource control message maycomprise the one or more beam configuration parameters.

FIG. 44 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. At 4410, a first distributed radio accessnetwork entity may receive a first message from a central radio accessnetwork entity. The first message may comprise one or more beamconfiguration parameters for a serving cell of the first distributedradio access network entity. The first message may be configured torequest at least one of: activation of a first beam, deactivation of asecond beam, and modification of a configuration of a third beam. At4420, the first distributed radio access network entity may transmit asecond message to the central radio access network entity and inresponse to the first message. The second message may indicate at leastone of: acceptance of the request of the first message, and rejection ofthe request of the first message. At 4430, the first distributed radioaccess network entity may configure beam configurations based on the oneor more beam configuration parameters. At 4440, the first distributedradio access network entity may transmit beam information to a pluralityof wireless devices. The beam information may be determined based on theone or more beam configuration parameters.

According to an embodiment, a third message may be received by thecentral radio access network entity from a first wireless device.According to an embodiment, a third message may be received by thecentral radio access network entity from a neighboring base station.According to an embodiment, a third message may be received by thecentral radio access network entity from the first distributed radioaccess network entity. According to an embodiment, a third message maybe received by the central radio access network entity from a seconddistributed radio access network entity.

According to an embodiment, the third message may comprise a resourcestatus information of one or more beams of one or more cells. Accordingto an embodiment, the third message may comprise a resource statusinformation of one or more cells. According to an embodiment, the thirdmessage may comprise a load status information of one or more beams ofone or more cells (e.g. a number of serving wireless devices, a numberof radio resource control inactive state wireless devices, a randomaccess resource utilization information, and/or the like). According toan embodiment, the third message may comprise a load status informationof one or more cells. According to an embodiment, the third message maycomprise an uplink receiving interference information of one or morebeams. According to an embodiment, the third message may comprise anuplink receiving interference information of one or more cells.According to an embodiment, the third message may comprise a downlinkreceiving interference information of one or more beams. According to anembodiment, the third message may comprise a downlink receivinginterference information of one or more cells.

According to an embodiment, the central radio access network entity maydetermine one or more elements of the first message based on the thirdmessage. According to an embodiment, a third message may be received bythe central radio access network entity from the first distributed radioaccess network entity. According to an embodiment, the central radioaccess network entity may transmit to a wireless device, a fourthmessage comprising one or more radio resource control configurationparameters based on the second message.

According to an embodiment, the one or more beam configurationparameters indicate a beam index. According to an embodiment, the one ormore beam configuration parameters indicate beam scheduling information.According to an embodiment, the one or more beam configurationparameters indicate a beam transmission power. According to anembodiment, the one or more beam configuration parameters indicate abeam steering direction.

FIG. 45 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. At 4510, a base station central unit maytransmit a first message to a wireless device via a base stationdistributed unit. The first message may comprise configurationparameters of the wireless device. At 4520, the base station centralunit may receive a second message from the wireless device via the basestation distributed unit. The second message may confirm at least one ofthe configuration parameters. At 4530, the base station central unit maytransmit a third message to the base station distributed unit. The thirdmessage may indicate that the wireless device successfully performed areconfiguration procedure based on the configuration parameters.

FIG. 46 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. At 4610, a base station distributed unit maydetermine that a first uplink timing advance value for a first cell of awireless device is different than a second uplink timing advance valuefor a second cell of the wireless device. The first cell and the secondcell may belong to a first timing advance group. At 4620, the basestation distributed unit may transmit a first message to a base stationcentral unit in response to the determining. The first message maycomprise one or more information elements. The one or more informationelements may indicate a reconfiguration of a timing advance groupconfiguration for the wireless device. At 4630, the base stationdistributed unit may receive from the base station central unit, a radioresource control message based on the reconfiguration for the wirelessdevice.

According to an embodiment, the radio resource control message mayindicate that the first timing advance group may comprise the firstcell. According to an embodiment, the radio resource control message mayindicate that a second timing advance group may comprise the secondcell. According to an embodiment, the base station central unit maycreate based on the first message, the second timing advance group forthe second cell. According to an embodiment, the base stationdistributed unit may receive from the wireless device: at least onefirst reference signal via the first cell and at least one secondreference signal via the second cell. The determining may be based on:the at least one first reference signal, and the at least one secondreference signal.

According to an embodiment, the at least one first reference signal maycomprise a sounding reference signal. According to an embodiment, the atleast one first reference signal may comprise a random access preamble.According to an embodiment, the at least one second reference signal maycomprise a sounding reference signal. According to an embodiment, the atleast one second reference signal may comprise a random access preamble.According to an embodiment, the base station distributed unit maytransmit to the base station central unit, configuration information mayindicate that the first timing advance group may comprise the first celland the second cell. According to an embodiment, the base stationdistributed unit may receive from the base station central unit, asecond radio resource control message. The second radio resource controlmessage may comprise the configuration information. According to anembodiment, the base station distributed unit may transmit to thewireless device, the second radio resource control message.

According to an embodiment, the base station distributed unit maytransmit the radio resource control message to the wireless device.According to an embodiment, the base station distributed unit maytransmit to the wireless device, a timing advance command for at leastone of: the first timing advance group of the first cell, or a secondtiming advance group of the second cell. According to an embodiment, thetiming advance command is transmitted via a medium access controlcontrol element. According to an embodiment, the second cell is servedby multiple transmission and reception points. According to anembodiment, the first message indicates at least one of: the firstuplink timing advance value is different than the second uplink timingadvance value, or the first cell and the second cell need to belong todifferent timing advance groups for the wireless device.

According to an embodiment, the first message further may comprise atleast one of: the first uplink timing advance value, the second uplinktiming advance value, or a difference value may indicate an amount ofdifference between the first uplink timing advance value and the seconduplink timing advance value. According to an embodiment, the firstuplink timing advance value indicates an amount of time to be adjustedfor uplink time alignment of the first cell. According to an embodiment,the second uplink timing advance value may indicate an amount of time tobe adjusted for uplink time alignment of the second cell. According toan embodiment, the first message further may comprise an identifier ofthe wireless device. According to an embodiment, the base stationdistributed unit may receive from the base station central unit, asecond message in response to the first message. The second message mayindicate acknowledgment of the one or more information elements.

According to an embodiment, the first message and the radio resourcecontrol message may be transmitted via an F1 interface between the basestation distributed unit and the base station central unit. According toan embodiment, the base station central unit may comprise a radioresource control function for the wireless device. According to anembodiment, the base station distributed unit may comprise at least oneof: a medium access control layer function for the wireless device, or aphysical layer function for the wireless device. According to anembodiment, the base station distributed unit may transmit to the basestation central unit, a configuration parameter. The configurationparameter may indicate at least one of: the first cell is served by afirst transmission and reception point, or the second cell is served by:the first transmission and reception point, a second transmission and/ora reception point. According to an embodiment, the base stationdistributed unit may decode the radio resource control message.

FIG. 47 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. At 4710, a base station distributed unit mayreceive from a wireless device, at least one first reference signal viaa first cell and at least one second reference signal via a second cell.The first cell and the second cell may be configured to belong to afirst timing advance group. At 4720, the base station distributed unitmay determine based on the at least one first reference signal and theat least one second reference signal, that a first uplink time alignmentvalue of the wireless device for the first cell is different than asecond uplink timing advance value of the wireless device for the secondcell. At 4730, the base station distributed unit may transmit a firstmessage to a base station central unit. The first message may compriseat least one of: the first uplink timing advance value is different thanthe second uplink timing advance value, the first uplink timing advancevalue and the second uplink timing advance value, a difference value mayindicate an amount of difference between the first uplink timing advancevalue and the second uplink timing advance value, or a timing advancegroup reconfiguration request for at least one of the first cell or thesecond cell.

According to an embodiment, the base station distributed unit mayreceive from the base station central unit, a second message in responseto the first message. The second message may indicate an acknowledgementfor one or more elements of the first message. According to anembodiment, the base station central unit may configure, based on thefirst message, the second cell to belong to a second timing advancegroup. According to an embodiment, the base station central unit maytransmit to the wireless device via the base station distributed unit, asecond message may indicate the second cell belongs to the second timingadvance group, wherein the second message may comprise a timing advancegroup identifier of the second timing advance group.

According to an embodiment, the base station distributed unit may decodethe second message. The base station distributed unit may transmit tothe wireless device, a timing advance command for the second cell withthe timing advance group identifier. According to an embodiment, thebase station distributed unit may receive third message from the basestation central unit. The third message may indicate the second cellbelongs to the second timing advance group. The third message maycomprise the timing advance group identifier. According to anembodiment, the base station distributed unit may transmit to thewireless device, a timing advance command with the timing advance groupidentifier for the second cell.

FIG. 48 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. At 4810, a base station central unit may receivetiming advance correlation information from a network entity. The timingadvance correlation information may comprise one or more cellidentifiers of one or more cells. The one or more cells may be served bya first transmission and reception point. At 4820, the base stationcentral unit may configure the one or more cells to belong to a firsttiming advance group for a wireless device in response to the one ormore cells being served by the first transmission and reception point.At 4830, the base station central unit may transmit radio resourcecontrol configuration information to the wireless device via a basestation distributed unit. The radio resource control configurationinformation may indicate that the one or more cells belong to the firsttiming advance group.

FIG. 49 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. At 4910, a base station central unit may receivetiming advance correlation information from a network entity. The timingadvance correlation information may comprise at least one identifier ofat least one timing advance correlation group. The timing advancecorrelation information may comprise a list of cells grouped into one ofthe at least one timing advance correlation group. The list of cells maycomprise an uplink timing advance value. At 4920, the base stationcentral unit may configure one or more cells to belong to a first timingadvance group for a wireless device in response to the one or more cellsbeing in the list of cells. At 4930, the base station central unit maytransmit radio resource control configuration information to thewireless device via a base station distributed unit. The radio resourcecontrol configuration information may indicate that a first cell of theone or more cells belongs to the first timing advance group.

According to an embodiment, the network entity may comprise at least oneof: the base station distributed unit, or an operation and maintenanceentity. According to an embodiment, the radio resource controlconfiguration information may comprise: a cell identifier of the firstcell, and a timing advance group identifier of the first timing advancegroup. According to an embodiment, the base station distributed unit maydecode the radio resource control configuration information. Accordingto an embodiment, the base station distributed unit may transmit to thewireless device: a timing advance command for the first cell, and thetiming advance group identifier of the first timing advance group.According to an embodiment, the base station distributed unit mayreceive from the base station central unit, a first message may indicatethat the first cell belongs to the first timing advance group, whereinthe first message may comprise the identifier of the first timingadvance group. According to an embodiment, the base station distributedunit may transmit to the wireless device: a timing advance command forthe first cell, and the timing advance group identifier of the firsttiming advance group.

FIG. 50 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. At 5010, a base station distributed unit maytransmit to a wireless device, a timing advance command for a timingadvance group. At 5020, the base station distributed unit may start inresponse to transmitting the timing advance command, a time alignmenttimer for the timing advance group of the wireless device. At 5030, thebase station distributed unit may determine expiration of the timealignment timer. At 5040, the base station distributed unit may transmita first message to a base station central unit. The first message mayindicate the expiration of the time alignment timer for the timingadvance group of the wireless device.

According to an embodiment, the timing advance group may comprise one ormore cells. According to an embodiment, in response to determining theexpiration of the time alignment timer, the base station distributedunit may release hybrid automated repeat request uplink resourceconfigurations for one or more cells of the timing advance group.According to an embodiment, in response to determining the expiration ofthe time alignment timer, the base station distributed unit may releasephysical uplink control channel configurations for one or more cells ofthe timing advance group. According to an embodiment, in response todetermining the expiration of the time alignment timer, the base stationdistributed unit may release sounding reference signal configurationsfor one or more cells of the timing advance group. According to anembodiment, in response to determining the expiration of the timealignment timer, the base station distributed unit may clear configureddownlink assignments for one or more cells of the timing advance group.According to an embodiment, in response to determining the expiration ofthe time alignment timer, the base station distributed unit may clearuplink resource grants for one or more cells of the timing advancegroup. According to an embodiment, in response to determining theexpiration of the time alignment timer, the base station distributedunit may determine, in response to the timing advance group being aprimary timing advance group, that a running time alignment timer forthe timing advance group is expired.

According to an embodiment, in response to the expiration of the timealignment timer, the base station distributed unit may apply a defaultphysical channel configuration for one or more cells of the timingadvance group. The default physical channel configuration may compriseat least one of: channel quality information report configurations. Thedefault physical channel configuration may comprise uplink resourcescheduling request configurations. The default physical channelconfiguration may comprise dedicated uplink sounding reference signalconfigurations.

According to an embodiment, the base station central unit may apply, inresponse to receiving the first message, a default physical channelconfiguration for one or more cells of the timing advance group. Thedefault physical channel configuration may comprise channel qualityinformation report configurations. The default physical channelconfiguration may comprise uplink resource scheduling requestconfigurations. The default physical channel configuration may comprisededicated uplink sounding reference signal configurations.

According to an embodiment, the base station distributed unit mayreceive a second message and based on the first message, a secondmessage may indicate a wireless device context release request for thewireless device. According to an embodiment, the base stationdistributed unit may release and in response to receiving the secondmessage, a wireless device context of the wireless device. The wirelessdevice context may comprise one or more data radio bearers. The wirelessdevice context may comprise one or more logical channels. The wirelessdevice context may comprise one or more security configurationparameters. The wireless device context may comprise one or moreinformation associated with the wireless device. According to anembodiment, the base station central unit may transmit the secondmessage in response to the timing advance group being a primary timingadvance group.

According to an embodiment, the base station distributed unit mayrelease and based on the expiration of the time alignment timer, awireless device context of the wireless device. The wireless devicecontext may comprise one or more data radio bearers. The wireless devicecontext may comprise one or more logical channels. The wireless devicecontext may comprise one or more security configuration parameters. Thewireless device context may comprise one or more information associatedwith the wireless device.

According to an embodiment, the base station central unit may transmitto a core network entity and based on the first message, a thirdmessage. The third message may indicate release of an interfaceconnection for the wireless device between the base station central unitand the core network entity. According to an embodiment, the basestation central unit may transmit the third message in response to thetiming advance group being a primary timing advance group. According toan embodiment, the core network entity may comprise an access andmobility management function. According to an embodiment, the corenetwork entity may comprise a mobility management function.

According to an embodiment, further may comprise releasing, by the basestation central unit may release and based on the first message, awireless device context of the wireless device. The wireless devicecontext may comprise one or more data radio bearers. The wireless devicecontext may comprise one or more logical channels. The wireless devicecontext may comprise one or more security configuration parameters. Thewireless device context may comprise one or more information associatedwith the wireless device.

According to an embodiment, the base station central unit and inresponse to receiving the first message, may release hybrid automatedrepeat request uplink resource configurations for one or more cells ofthe timing advance group. According to an embodiment, the base stationcentral unit and in response to receiving the first message, may releasephysical uplink control channel configurations for one or more cells ofthe timing advance group. According to an embodiment, the base stationcentral unit and in response to receiving the first message, may releasesounding reference signal configurations for one or more cells of thetiming advance group. According to an embodiment, the base stationcentral unit and in response to receiving the first message, may clearconfigured downlink assignments for one or more cells of the timingadvance group. According to an embodiment, the base station central unitand in response to receiving the first message, may clear uplinkresource grants for one or more cells of the timing advance group.According to an embodiment, the base station central unit and inresponse to receiving the first message, may determine, in response tothe timing advance group being a primary timing advance group, that arunning time alignment timer for the timing advance group is expired.

According to an embodiment, the base station central unit may comprise aradio resource control function for the wireless device. According to anembodiment, the base station distributed unit may comprise a mediumaccess control layer function for the wireless device. According to anembodiment, the base station distributed unit may comprise a physicallayer function for the wireless device.

According to an embodiment, the transmitting of the first message may bevia an F1 interface. According to an embodiment, the transmitting of thetiming advance command may be via a medium access control controlelement. According to an embodiment, the time alignment timer may beconfigured by the base station central unit. According to an embodiment,the time alignment timer may be configured by the base stationdistributed unit. According to an embodiment, a base station maycomprise the base station central unit and the base station distributedunit. According to an embodiment, the base station central unit maytransmit to the wireless device, the time alignment timer via the basestation distributed unit. According to an embodiment, the first messagefurther may comprise an identifier of the wireless device. According toan embodiment, the first message further may comprise one or more cellidentifiers of one or more cells of the timing advance group. Accordingto an embodiment, the first message further may comprise a timingadvance group identifier of the timing advance group.

FIG. 51 is an example flow diagram as per an aspect of an embodiment ofthe present disclosure. At 5110, a base station distributed unit maytransmit to a wireless device, a timing advance command for a timingadvance group. At 5120, starting, by the base station distributed unitmay start and in response to transmitting the timing advance command, atime alignment timer for the timing advance group of the wirelessdevice. At 5130, the base station distributed unit may determineexpiration of the time alignment timer. At 5140, the base stationdistributed unit may transmit a first message to a base station centralunit in response to the expiration. The first message may indicate arequest for releasing physical uplink control channel configurations ofthe wireless device for one or more cells of the timing advance group,The first message may indicate a request for releasing soundingreference signal configurations of the wireless device for the one ormore cells.

Embodiments may be configured to operate as needed. The disclosedmechanism may be performed when certain criteria are met, for example,in a wireless device, a base station, a radio environment, a network, acombination of the above, and/or the like. Example criteria may bebased, at least in part, on for example, wireless device or network nodeconfigurations, traffic load, initial system set up, packet sizes,traffic characteristics, a combination of the above, and/or the like.When the one or more criteria are met, various example embodiments maybe applied. Therefore, it may be possible to implement exampleembodiments that selectively implement disclosed protocols.

A base station may communicate with a mix of wireless devices. Wirelessdevices and/or base stations may support multiple technologies, and/ormultiple releases of the same technology. Wireless devices may have somespecific capability(ies) depending on wireless device category and/orcapability(ies). A base station may comprise multiple sectors. When thisdisclosure refers to a base station communicating with a plurality ofwireless devices, this disclosure may refer to a subset of the totalwireless devices in a coverage area. This disclosure may refer to, forexample, a plurality of wireless devices of a given LTE or 5G releasewith a given capability and in a given sector of the base station. Theplurality of wireless devices in this disclosure may refer to a selectedplurality of wireless devices, and/or a subset of total wireless devicesin a coverage area which perform according to disclosed methods, and/orthe like. There may be a plurality of base stations or a plurality ofwireless devices in a coverage area that may not comply with thedisclosed methods, for example, because those wireless devices or basestations perform based on older releases of LTE or 5G technology.

In this disclosure, “a” and “an” and similar phrases are to beinterpreted as “at least one” and “one or more.” Similarly, any termthat ends with the suffix “(s)” is to be interpreted as “at least one”and “one or more.” In this disclosure, the term “may” is to beinterpreted as “may, for example.” In other words, the term “may” isindicative that the phrase following the term “may” is an example of oneof a multitude of suitable possibilities that may, or may not, beemployed to one or more of the various embodiments.

If A and B are sets and every element of A is also an element of B, A iscalled a subset of B. In this specification, only non-empty sets andsubsets are considered. For example, possible subsets of B ={cell1,cell2} are: {cell1}, {cell2}, and {cell1, cell2}. The phrase “based on”(or equally “based at least on”) is indicative that the phrase followingthe term “based on” is an example of one of a multitude of suitablepossibilities that may, or may not, be employed to one or more of thevarious embodiments. The phrase “in response to” (or equally “inresponse at least to”) is indicative that the phrase following thephrase “in response to” is an example of one of a multitude of suitablepossibilities that may, or may not, be employed to one or more of thevarious embodiments. The phrase “depending on” (or equally “depending atleast to”) is indicative that the phrase following the phrase “dependingon” is an example of one of a multitude of suitable possibilities thatmay, or may not, be employed to one or more of the various embodiments.The phrase “employing/using” (or equally “employing/using at least”) isindicative that the phrase following the phrase “employing/using” is anexample of one of a multitude of suitable possibilities that may, or maynot, be employed to one or more of the various embodiments.

The term configured may relate to the capacity of a device whether thedevice is in an operational or non-operational state. Configured mayalso refer to specific settings in a device that effect the operationalcharacteristics of the device whether the device is in an operational ornon-operational state. In other words, the hardware, software, firmware,registers, memory values, and/or the like may be “configured” within adevice, whether the device is in an operational or nonoperational state,to provide the device with specific characteristics. Terms such as “acontrol message to cause in a device” may mean that a control messagehas parameters that may be used to configure specific characteristics ormay be used to implement certain actions in the device, whether thedevice is in an operational or non-operational state

In this disclosure, various embodiments are disclosed. Limitations,features, and/or elements from the disclosed example embodiments may becombined to create further embodiments within the scope of thedisclosure.

In this disclosure, parameters (or equally called, fields, orInformation elements: IEs) may comprise one or more information objects,and an information object may comprise one or more other objects. Forexample, if parameter (IE) N comprises parameter (IE) M, and parameter(IE) M comprises parameter (IE) K, and parameter (IE) K comprisesparameter (information element) J. Then, for example, N comprises K, andN comprises J. In an example embodiment, when one or more (or at leastone) message(s) comprise a plurality of parameters, it implies that aparameter in the plurality of parameters is in at least one of the oneor more messages, but does not have to be in each of the one or moremessages. In an example embodiment, when one or more (or at least one)message(s) indicate a value, event and/or condition, it implies that thevalue, event and/or condition is indicated by at least one of the one ormore messages, but does not have to be indicated by each of the one ormore messages.

Furthermore, many features presented above are described as beingoptional through the use of “may” or the use of parentheses. For thesake of brevity and legibility, the present disclosure does notexplicitly recite each and every permutation that may be obtained bychoosing from the set of optional features. However, the presentdisclosure is to be interpreted as explicitly disclosing all suchpermutations. For example, a system described as having three optionalfeatures may be embodied in seven different ways, namely with just oneof the three possible features, with any two of the three possiblefeatures or with all three of the three possible features.

Many of the elements described in the disclosed embodiments may beimplemented as modules. A module is defined here as an element thatperforms a defined function and has a defined interface to otherelements. The modules described in this disclosure may be implemented inhardware, software in combination with hardware, firmware, wetware (i.e.hardware with a biological element) or a combination thereof, all ofwhich may be behaviorally equivalent. For example, modules may beimplemented as a software routine written in a computer languageconfigured to be executed by a hardware machine (such as C, C++,Fortran, Java, Basic, Matlab or the like) or a modeling/simulationprogram such as Simulink, Stateflow, GNU Octave, or LabVIEWMathScript.Additionally, it may be possible to implement modules using physicalhardware that incorporates discrete or programmable analog, digitaland/or quantum hardware. Examples of programmable hardware comprise:computers, microcontrollers, microprocessors, application-specificintegrated circuits (ASICs); field programmable gate arrays (FPGAs); andcomplex programmable logic devices (CPLDs). Computers, microcontrollersand microprocessors are programmed using languages such as assembly, C,C++ or the like. FPGAs, ASICs and CPLDs are often programmed usinghardware description languages (HDL) such as VHSIC hardware descriptionlanguage (VHDL) or Verilog that configure connections between internalhardware modules with lesser functionality on a programmable device. Theabove mentioned technologies are often used in combination to achievethe result of a functional module.

The disclosure of this patent document incorporates material which issubject to copyright protection. The copyright owner has no objection tothe facsimile reproduction by anyone of the patent document or thepatent disclosure, as it appears in the Patent and Trademark Officepatent file or records, for the limited purposes required by law, butotherwise reserves all copyright rights whatsoever.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example, and notlimitation. It will be apparent to persons skilled in the relevantart(s) that various changes in form and detail can be made thereinwithout departing from the scope. In fact, after reading the abovedescription, it will be apparent to one skilled in the relevant art(s)how to implement alternative embodiments. Thus, the present embodimentsshould not be limited by any of the above described exemplaryembodiments.

In addition, it should be understood that any figures which highlightthe functionality and advantages, are presented for example purposesonly. The disclosed architecture is sufficiently flexible andconfigurable, such that it may be utilized in ways other than thatshown. For example, the actions listed in any flowchart may bere-ordered or only optionally used in some embodiments.

Further, the purpose of the Abstract of the Disclosure is to enable theU.S. Patent and Trademark Office and the public generally, andespecially the scientists, engineers and practitioners in the art whoare not familiar with patent or legal terms or phraseology, to determinequickly from a cursory inspection the nature and essence of thetechnical disclosure of the application. The Abstract of the Disclosureis not intended to be limiting as to the scope in any way.

Finally, it is the applicant's intent that only claims that include theexpress language “means for” or “step for” be interpreted under 35U.S.C. 112. Claims that do not expressly include the phrase “means for”or “step for” are not to be interpreted under 35 U.S.C. 112.

What is claimed is:
 1. A method comprising: transmitting, by a basestation distributed unit to a wireless device, a timing advance commandfor a timing advance group; starting, by the base station distributedunit and in response to transmitting the timing advance command, a timealignment timer for the timing advance group of the wireless device;determining, by the base station distributed unit, expiration of thetime alignment timer; and transmitting, by the base station distributedunit to a base station central unit, a first message indicating theexpiration of the time alignment timer for the timing advance group ofthe wireless device.
 2. The method of claim 1, wherein the timingadvance group comprises one or more cells.
 3. The method of claim 1,further comprising, by the base station distributed unit and in responseto determining the expiration of the time alignment timer, at least oneof: releasing hybrid automated repeat request uplink resourceconfigurations for one or more cells of the timing advance group;releasing physical uplink control channel configurations for one or morecells of the timing advance group; releasing sounding reference signalconfigurations for one or more cells of the timing advance group;clearing configured downlink assignments for one or more cells of thetiming advance group; clearing uplink resource grants for one or morecells of the timing advance group; or determining, in response to thetiming advance group being a primary timing advance group, that arunning time alignment timer for the timing advance group is expired. 4.The method of claim 1, further comprising applying, by the base stationdistributed unit and in response to the expiration of the time alignmenttimer, a default physical channel configuration for one or more cells ofthe timing advance group, wherein the default physical channelconfiguration comprises at least one of: channel quality informationreport configurations; uplink resource scheduling requestconfigurations; or dedicated uplink sounding reference signalconfigurations.
 5. The method of claim 1, further comprising applying,by the base station central unit and in response to receiving the firstmessage, a default physical channel configuration for one or more cellsof the timing advance group, wherein the default physical channelconfiguration comprises at least one of: channel quality informationreport configurations; uplink resource scheduling requestconfigurations; or dedicated uplink sounding reference signalconfigurations.
 6. The method of claim 1, further comprising: receiving,by the base station distributed unit and based on the first message, asecond message indicating a wireless device context release request forthe wireless device; and releasing, by the base station distributed unitand in response to receiving the second message, a wireless devicecontext of the wireless device, wherein the wireless device contextcomprises at least one of: one or more data radio bearers; one or morelogical channels; one or more security configuration parameters; or oneor more information associated with the wireless device.
 7. The methodof claim 6, further comprising transmitting, by the base station centralunit, the second message in response to the timing advance group being aprimary timing advance group.
 8. The method of claim 1, furthercomprising releasing, by the base station distributed unit and based onthe expiration of the time alignment timer, a wireless device context ofthe wireless device, wherein the wireless device context comprises atleast one of: one or more data radio bearers; one or more logicalchannels; one or more security configuration parameters; or one or moreinformation associated with the wireless device.
 9. The method of claim1, further comprising transmitting, by the base station central unit toa core network entity and based on the first message, a third messageindicating release of an interface connection for the wireless devicebetween the base station central unit and the core network entity. 10.The method of claim 9, further comprising transmitting, by the basestation central unit, the third message in response to the timingadvance group being a primary timing advance group.
 11. The method ofclaim 9, wherein the core network entity comprises at least one of: anaccess and mobility management function; or a mobility managementfunction.
 12. The method of claim 1, further comprising releasing, bythe base station central unit and based on the first message, a wirelessdevice context of the wireless device, wherein the wireless devicecontext comprises at least one of: one or more data radio bearers; oneor more logical channels; one or more security configuration parameters;or one or more information associated with the wireless device.
 13. Themethod of claim 1, further comprising, by the base station central unitand in response to receiving the first message, at least one of:releasing hybrid automated repeat request uplink resource configurationsfor one or more cells of the timing advance group; releasing physicaluplink control channel configurations for one or more cells of thetiming advance group; releasing sounding reference signal configurationsfor one or more cells of the timing advance group; clearing configureddownlink assignments for one or more cells of the timing advance group;clearing uplink resource grants for one or more cells of the timingadvance group; or determining, in response to the timing advance groupbeing a primary timing advance group, that a running time alignmenttimer for the timing advance group is expired.
 14. The method of claim1, wherein: the base station central unit comprises a radio resourcecontrol function for the wireless device; and the base stationdistributed unit comprises at least one of: a medium access controllayer function for the wireless device; or a physical layer function forthe wireless device.
 15. The method of claim 1, wherein the transmittingof the first message is via an F1 interface.
 16. The method of claim 1,wherein the transmitting of the timing advance command is via a mediumaccess control control element.
 17. The method of claim 1, wherein thetime alignment timer is configured by at least one of: the base stationcentral unit; or the base station distributed unit.
 18. The method ofclaim 1, wherein a base station comprises the base station central unitand the base station distributed unit.
 19. The method of claim 1,further comprising transmitting, by the base station central unit to thewireless device, the time alignment timer via the base stationdistributed unit.
 20. The method of claim 1, wherein the first messagefurther comprises at least one of: an identifier of the wireless device;one or more cell identifiers of one or more cells of the timing advancegroup; or a timing advance group identifier of the timing advance group.